{ "spore": "profile", "id": "nimnga-shape-memory", "spore_version": "0.2", "family": "nickel-manganese-gallium-heusler", "name": "Nickel-manganese-gallium magnetic shape-memory alloy", "abbreviation": "Ni-Mn-Ga", "role": "magnetic shape-memory alloy for actuators and magnetocaloric cooling", "category": "metals", "type": "shape-memory-alloys", "summary": "Ni-Mn-Ga is a Heusler alloy of nickel, manganese and gallium, with stoichiometric Ni2MnGa as its reference composition. Unlike nitinol, which changes shape on heating, its martensite can be reoriented by a magnetic field. Single crystals of Ni48 Mn31 Ga21, Ni49.8 Mn28.5 Ga21.7 and Ni48.2 Mn30.8 Ga21 gave 5.1, 6.0 and 7.3 % magnetically induced strain in one review table. The Curie temperature of stoichiometric Ni2MnGa is about 370 K, and the martensitic transition temperature of the Ni2+xMn1-xGa series rises from 201 K at x = 0 to 342 K at x = 0.19.\n", "best_for": "Single-crystal actuators that must move by a magnetic field rather than by heating, with 5.1 to 7.3 % magnetically induced strain in the review table and a martensite that is magnetically controlled", "weakest_at": "Brittleness and a low martensitic transformation temperature. A 2000 MRS-J paper names both as the main obstacles to practical use, and strain is lost when the crystal is cut from the middle of the boule", "identity": { "formula": "Ni2MnGa, stoichiometric Heusler alloy; the studied series is Ni2+xMn1-xGa with x from 0 to 0.19", "designations": [], "source": "khovailo2004", "where": "Abstract and composition formula Ni2+xMn1-xGa, 0 to 0.19; Ni2MnGa at x = 0 (introduction)" }, "tags": { "environments": [], "stresses": [], "applications": [ "mechanisms", "thermal-control" ] }, "properties": [ { "benchmark": "curie_temperature", "label": "Curie temperature, stoichiometric Ni2MnGa", "value": 370, "bound": "exact", "unit": "K", "scope": "material", "conditions": { "composition": "Ni2MnGa, x = 0", "note": "printed as about 370 K" }, "method": "Value stated in the text on the composition dependence of TC, from magnetization measurements reported in the paper", "status": "ground", "source": "khovailo2004", "where": "Text on composition dependence, sentence beginning The Curie temperature TC is about 370 K in stoichiometric composition", "source_detail": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "martensitic_transition_temperature", "label": "Martensitic transition temperature Tm, x = 0 (Ni2MnGa)", "value": 201, "bound": "exact", "unit": "K", "scope": "material", "conditions": { "composition": "Ni2+xMn1-xGa, x = 0" }, "method": "Tm column of Table I in the paper, which gives the transition temperature for each composition", "status": "ground", "source": "khovailo2004", "where": "Table I, Tm column, row x = 0", "source_detail": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "martensitic_transition_temperature", "label": "Martensitic transition temperature Tm, x = 0.04", "value": 237, "bound": "exact", "unit": "K", "scope": "material", "conditions": { "composition": "Ni2+xMn1-xGa, x = 0.04" }, "method": "Tm column of Table I in the paper", "status": "ground", "source": "khovailo2004", "where": "Table I, Tm column, row x = 0.04", "source_detail": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "martensitic_transition_temperature", "label": "Martensitic transition temperature Tm, x = 0.08", "value": 265, "bound": "exact", "unit": "K", "scope": "material", "conditions": { "composition": "Ni2+xMn1-xGa, x = 0.08" }, "method": "Tm column of Table I in the paper", "status": "ground", "source": "khovailo2004", "where": "Table I, Tm column, row x = 0.08", "source_detail": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "martensitic_transition_temperature", "label": "Martensitic transition temperature Tm, x = 0.12", "value": 294, "bound": "exact", "unit": "K", "scope": "material", "conditions": { "composition": "Ni2+xMn1-xGa, x = 0.12" }, "method": "Tm column of Table I in the paper", "status": "ground", "source": "khovailo2004", "where": "Table I, Tm column, row x = 0.12", "source_detail": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "martensitic_transition_temperature", "label": "Martensitic transition temperature Tm, x = 0.16", "value": 315, "bound": "exact", "unit": "K", "scope": "material", "conditions": { "composition": "Ni2+xMn1-xGa, x = 0.16" }, "method": "Tm column of Table I in the paper", "status": "ground", "source": "khovailo2004", "where": "Table I, Tm column, row x = 0.16", "source_detail": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "martensitic_transition_temperature", "label": "Martensitic transition temperature Tm, x = 0.19", "value": 342, "bound": "exact", "unit": "K", "scope": "material", "conditions": { "composition": "Ni2+xMn1-xGa, x = 0.19" }, "method": "Tm column of Table I in the paper; at x = 0.18 to 0.19 the Curie temperature merges with Tm", "status": "ground", "source": "khovailo2004", "where": "Table I, Tm column, row x = 0.19", "source_detail": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "latent_heat_martensitic_transition", "label": "Latent heat of the martensitic transition, x = 0", "value": 270, "bound": "exact", "unit": "J/mol", "scope": "material", "conditions": { "composition": "Ni2+xMn1-xGa, x = 0" }, "method": "Q column of Table I in the paper, which the text links to the latent heat used in the Clapeyron-Clausius analysis", "status": "ground", "source": "khovailo2004", "where": "Table I, Q column, row x = 0", "source_detail": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "latent_heat_martensitic_transition", "label": "Latent heat of the martensitic transition, x = 0.19", "value": 2260, "bound": "exact", "unit": "J/mol", "scope": "material", "conditions": { "composition": "Ni2+xMn1-xGa, x = 0.19" }, "method": "Q column of Table I in the paper", "status": "ground", "source": "khovailo2004", "where": "Table I, Q column, row x = 0.19", "source_detail": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "magnetic_field_induced_strain", "label": "Magnetically induced strain, Ni48 Mn31 Ga21 single crystal", "value": 5.1, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "composition": "Ni48 Mn31 Ga21 (at.%), single crystal, single-variant martensite", "note": "strain in the martensitic state set by variant reorientation in a magnetic field" }, "method": "MFIS column of Table I in the review, which collects single-crystal values; the table lists references 74 and 135 for this row", "status": "ground", "source": "vasil2003", "where": "Table I, Magnetically induced strains in Ni2+x+yMn1-xGa1-y alloys, row Ni48 Mn31 Ga21", "source_detail": { "title": "Shape memory ferromagnets (Vasil'ev et al., arXiv cond-mat/0311433, 2003)", "url": "https://arxiv.org/pdf/cond-mat/0311433", "year": 2003, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "magnetic_field_induced_strain", "label": "Magnetically induced strain, Ni49.8 Mn28.5 Ga21.7 single crystal", "value": 6, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "composition": "Ni49.8 Mn28.5 Ga21.7 (at.%), single crystal" }, "method": "MFIS column of Table I in the review; the table cites reference 119 for this row", "status": "ground", "source": "vasil2003", "where": "Table I, Magnetically induced strains, row Ni49.8 Mn28.5 Ga21.7", "source_detail": { "title": "Shape memory ferromagnets (Vasil'ev et al., arXiv cond-mat/0311433, 2003)", "url": "https://arxiv.org/pdf/cond-mat/0311433", "year": 2003, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "magnetic_field_induced_strain", "label": "Magnetically induced strain, Ni48.2 Mn30.8 Ga21 single crystal", "value": 7.3, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "composition": "Ni48.2 Mn30.8 Ga21 (at.%), single crystal" }, "method": "MFIS column of Table I in the review; the table cites reference 81 for this row", "status": "ground", "source": "vasil2003", "where": "Table I, Magnetically induced strains, row Ni48.2 Mn30.8 Ga21", "source_detail": { "title": "Shape memory ferromagnets (Vasil'ev et al., arXiv cond-mat/0311433, 2003)", "url": "https://arxiv.org/pdf/cond-mat/0311433", "year": 2003, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "magnetic_field_induced_strain", "label": "Magnetically induced strain, nonmodulated martensite single crystal", "value": 0.17, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "composition": "Ni53.1 Mn26.6 Ga20.3 (composition as printed, no at.% stated), single crystal, stress-free", "field": "rotating magnetic field, strength not stated in the abstract" }, "method": "Abstract value for a rotating field on a stress-free single crystal with nonmodulated martensite", "status": "ground", "source": "chernenko2009", "where": "Abstract, first sentence", "source_detail": { "title": "Large Magnetic-Field-Induced Strains in Ni-Mn-Ga Nonmodulated Martensite (Chernenko, Chmielus, Mullner, Applied Physics Letters 95, 104103, 2009)", "url": "https://scholarworks.boisestate.edu/mse_facpubs/40", "year": 2009, "kind": "paper", "license": "author repository (cited, not reproduced)" } }, { "benchmark": "martensitic_transition_temperature", "label": "Martensitic transition temperature Ms, Ni48 Mn31 Ga21", "value": 301, "bound": "exact", "unit": "K", "scope": "material", "conditions": { "composition": "Ni48 Mn31 Ga21 (at.%)", "note": "Ms as printed in Table I of the review" }, "method": "Ms column of Table I in the review, shown with the MFIS value for the same row", "status": "ground", "source": "vasil2003", "where": "Table I, Ms column, row Ni48 Mn31 Ga21", "source_detail": { "title": "Shape memory ferromagnets (Vasil'ev et al., arXiv cond-mat/0311433, 2003)", "url": "https://arxiv.org/pdf/cond-mat/0311433", "year": 2003, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "martensitic_transition_temperature", "label": "Martensitic transition temperature Ms, Ni49.8 Mn28.5 Ga21.7", "value": 318, "bound": "exact", "unit": "K", "scope": "material", "conditions": { "composition": "Ni49.8 Mn28.5 Ga21.7 (at.%)", "note": "Ms as printed in Table I of the review" }, "method": "Ms column of Table I in the review, shown with the MFIS value for the same row", "status": "ground", "source": "vasil2003", "where": "Table I, Ms column, row Ni49.8 Mn28.5 Ga21.7", "source_detail": { "title": "Shape memory ferromagnets (Vasil'ev et al., arXiv cond-mat/0311433, 2003)", "url": "https://arxiv.org/pdf/cond-mat/0311433", "year": 2003, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "magnetocrystalline_anisotropy_constant", "label": "Uniaxial anisotropy constant Ku at room temperature, Ni48 Mn31 Ga21", "value": 1.7, "bound": "exact", "unit": "10^6 erg/cm3", "scope": "material", "conditions": { "composition": "Ni48 Mn31 Ga21 (at.%), single-variant state", "temperature": "room temperature", "unit_in_source": "10^6 erg/cm3" }, "method": "Ku value given in the review text for single-variant single crystals of this composition, and in the Ku column of Table I", "status": "ground", "source": "vasil2003", "where": "Section on magnetocrystalline anisotropy, paragraph beginning with the values of Ku at room temperature", "source_detail": { "title": "Shape memory ferromagnets (Vasil'ev et al., arXiv cond-mat/0311433, 2003)", "url": "https://arxiv.org/pdf/cond-mat/0311433", "year": 2003, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "magnetocrystalline_anisotropy_constant", "label": "Uniaxial anisotropy constant Ku at room temperature, Ni48.2 Mn30.8 Ga21", "value": 2.13, "bound": "exact", "unit": "10^6 erg/cm3", "scope": "material", "conditions": { "composition": "Ni48.2 Mn30.8 Ga21 (at.%)", "unit_in_source": "10^6 erg/cm3" }, "method": "Ku column of Table I in the review, with reference 81", "status": "ground", "source": "vasil2003", "where": "Table I, Ku column, row Ni48.2 Mn30.8 Ga21", "source_detail": { "title": "Shape memory ferromagnets (Vasil'ev et al., arXiv cond-mat/0311433, 2003)", "url": "https://arxiv.org/pdf/cond-mat/0311433", "year": 2003, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "magnetic_entropy_change", "label": "Magnetic entropy change at the transition, field switched on", "value": 9, "bound": "exact", "unit": "J/kgK", "scope": "material", "conditions": { "composition": "Ni-Mn-Ga alloy (composition not stated on the page)", "field": "26 kOe", "temperature": "338 K on turning the field on" }, "method": "Largest entropy change in a 26 kOe field, as stated in the conference summary", "status": "ground", "source": "aliev2005", "where": "Summary, first sentence on entropy changes", "source_detail": { "title": "Magnetocaloric effect in Ni-Mn-Ga Heusler alloys (Aliev et al., 1st International Conference on Magnetic Refrigeration at Room Temperature, 2005)", "url": "https://iifiir.org/en/fridoc/magnetocaloric-effect-in-ni-mn-ga-heusler-alloys-22416", "year": 2005, "kind": "paper", "license": "IIR document (cited, not reproduced)" } }, { "benchmark": "magnetic_entropy_change", "label": "Magnetic entropy change at the transition, field switched off", "value": 11, "bound": "exact", "unit": "J/kgK", "scope": "material", "conditions": { "composition": "Ni-Mn-Ga alloy (composition not stated on the page)", "field": "26 kOe", "temperature": "344 K on turning the field off" }, "method": "Largest entropy change in a 26 kOe field on field removal, as stated in the conference summary", "status": "ground", "source": "aliev2005", "where": "Summary, second sentence on entropy changes", "source_detail": { "title": "Magnetocaloric effect in Ni-Mn-Ga Heusler alloys (Aliev et al., 1st International Conference on Magnetic Refrigeration at Room Temperature, 2005)", "url": "https://iifiir.org/en/fridoc/magnetocaloric-effect-in-ni-mn-ga-heusler-alloys-22416", "year": 2005, "kind": "paper", "license": "IIR document (cited, not reproduced)" } } ], "corrosion": [], "risks": { "hazards": [ { "text": "Gallium, the Ga constituent: the supplier safety data sheet lists H290 (may be corrosive to metals) with signal word Warning, and P234, P390 and P406.", "ghs": [ "H290" ], "source": "sds-ga", "where": "Section 2, hazard statements; precautionary statements" }, { "text": "Nickel-based alloy SDS, the closest found for a nickel-rich alloy and not Ni-Mn-Ga itself: skin sensitisation Category 1 (H317), carcinogenicity Category 2 (H351), STOT repeated exposure Category 1 (H372) and aquatic chronic Category 1 (H410).", "ghs": [ "H317", "H351", "H372", "H410" ], "source": "sds-ni-alloy", "where": "Section 2.1, classification of the substance or mixture" } ], "failure_risks": [ { "mode": "Brittleness", "trigger": "Ni-Mn-Ga Heusler alloys processed for actuators", "consequence": "The 2000 MRS-J paper calls inherent brittleness, together with lower martensitic transformation temperatures, a problem to be overcome before practical use.", "severity": "high", "source": "tsuchiya2000", "where": "Introduction, first paragraph" }, { "mode": "Loss of strain from sample position", "trigger": "Single crystal cut from the middle of the boule instead of its beginning", "consequence": "For samples cut from the middle of the single crystals no magnetically induced strain was observed, while a 6 % strain was seen in a sample cut from the beginning.", "severity": "moderate", "source": "vasil2003", "where": "Section on magnetically induced strains, paragraph after Table I reference 141" }, { "mode": "Composition shift of the transition", "trigger": "Excess nickel, x in Ni2+xMn1-xGa, from 0 toward 0.19", "consequence": "Tm rises from 201 K to 342 K and the Curie temperature falls toward the same value, so at x = 0.18 to 0.19 the alloy goes from paramagnetic austenite to martensite through a structural transition.", "severity": "high", "source": "khovailo2004", "where": "Introduction and Table I" }, { "mode": "No strain when the anisotropy is too weak", "trigger": "Magnetocrystalline anisotropy energy below the effective elastic modulus of the twin boundaries", "consequence": "Variant reorientation needs the anisotropy energy density to exceed the effective elastic modulus of the displacement of martensitic domain boundaries, so weaker anisotropy gives less strain.", "severity": "moderate", "source": "vasil2003", "where": "Section on magnetically induced strains, paragraph beginning This occurs if the magnetocrystalline anisotropy energy density exceeds" } ], "side_effects": [], "handling": [ { "text": "Melt the alloy in an argon arc, then homogenize the ingot at 1073 K for 48 to 72 hours in argon and quench into room-temperature water.", "source": "tsuchiya2000", "where": "Experimental section" }, { "text": "Check composition by EDX after melting, because the transition temperature moves with the Ni, Mn and Ga content.", "source": "tsuchiya2000", "where": "Experimental section, composition analysis" }, { "text": "Treat gallium as corrosive to metals (H290) and follow the supplier SDS for the alloy.", "source": "sds-ga", "where": "Section 2" } ], "mitigations": [] }, "uses": [ { "application": "mechanisms", "device": "Magnetic actuators and magnetomechanical parts", "example": "The 2000 MRS-J paper calls Ni-Mn-Ga a good candidate for magnetic actuator materials, because the alloy shows large twinning magnetostriction in its martensite phase.", "source": "tsuchiya2000", "where": "Introduction, first paragraph" }, { "application": "thermal-control", "device": "Magnetocaloric refrigerant", "example": "A 2005 conference paper on Ni-Mn-Ga reports magnetic entropy changes of 9 J/kgK at 338 K and 11 J/kgK at 344 K in a 26 kOe field, the basis for magnetic refrigeration at room temperature.", "source": "aliev2005", "where": "Summary" } ], "supply": [ { "subject": "Nickel, world mine production 2025e (3,900,000 t; Indonesia 2,600,000 t, Philippines 270,000 t, Russia 200,000 t, New Caledonia 140,000 t); shares calculated by Space Mushroom from the printed tonnages", "abundance": "World nickel reserves above 140,000,000 t (USGS 2026, reserves table)", "producers": [ { "country": "Indonesia", "share_percent": 66.7, "year": 2025 }, { "country": "Philippines", "share_percent": 6.9, "year": 2025 }, { "country": "Russia", "share_percent": 5.1, "year": 2025 } ], "critical_lists": [], "recycling": "USGS 2026: most secondary nickel was in the form of nickel content of stainless-steel scrap, and most recycled nickel was used to produce new alloys.", "substitutes": [], "source": "usgs-ni", "where": "World Mine Production and Reserves table, 2024 and 2025e columns" }, { "subject": "Manganese, world mine production 2025e (20,000 thousand t, manganese content; South Africa 7,600, Gabon 5,000, Ghana 2,000); shares calculated by Space Mushroom from the printed tonnages", "abundance": "Land-based manganese resources are large but irregularly distributed; world reserves 1,800,000 thousand t (USGS 2026)", "producers": [ { "country": "South Africa", "share_percent": 38, "year": 2025 }, { "country": "Gabon", "share_percent": 25, "year": 2025 }, { "country": "Ghana", "share_percent": 10, "year": 2025 } ], "critical_lists": [], "recycling": "USGS 2026: manganese was recycled incidentally as a constituent of ferrous and nonferrous scrap.", "substitutes": [], "source": "usgs-mn", "where": "World Mine Production (manganese content) and Reserves table, 2025e column" }, { "subject": "Gallium, world primary low-purity production 2024 (848,000 kg; China 839,000 kg, Japan 3,000 kg, Russia 6,000 kg); shares calculated by Space Mushroom from the printed kilograms", "abundance": "Gallium is produced mainly as a byproduct of bauxite processing; bauxite contains about 50 parts per million gallium (USGS 2026)", "producers": [ { "country": "China", "share_percent": 98.9, "year": 2024 }, { "country": "Russia", "share_percent": 0.7, "year": 2024 }, { "country": "Japan", "share_percent": 0.4, "year": 2024 } ], "critical_lists": [], "recycling": "USGS 2026: old scrap, none; substantial new scrap from GaAs device manufacture was reprocessed at one New York facility.", "substitutes": [], "source": "usgs-ga", "where": "World Low-Purity Production table, 2024 column; World Resources paragraph" } ], "media": [], "documents": [ { "title": "Shape memory ferromagnets (Vasil'ev et al., arXiv cond-mat/0311433, 2003)", "type": "paper", "url": "https://arxiv.org/pdf/cond-mat/0311433", "year": 2003 }, { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., arXiv cond-mat/0405134, 2004)", "type": "paper", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004 }, { "title": "Large Magnetic-Field-Induced Strains in Ni-Mn-Ga Nonmodulated Martensite (Chernenko et al., Applied Physics Letters 2009)", "type": "paper", "url": "https://scholarworks.boisestate.edu/mse_facpubs/40", "year": 2009 }, { "title": "Magnetocaloric effect in Ni-Mn-Ga Heusler alloys (Aliev et al., 2005)", "type": "paper", "url": "https://iifiir.org/en/fridoc/magnetocaloric-effect-in-ni-mn-ga-heusler-alloys-22416", "year": 2005 }, { "title": "Effect of Fourth Elements on Phase Transformations in Ni-Mn-Ga Heusler Alloys (Tsuchiya et al., Trans. MRS-J 25, 2000)", "type": "paper", "url": "https://www.mrs-j.org/pub/tmrsj/vol25_no2/vol25_no2_517.pdf", "year": 2000 }, { "title": "Structural, Thermal and Magnetic Characterization of Polycrystalline Ni-Mn-Ga Ferromagnetic Shape Memory Alloys (Materials Research, 2023)", "type": "paper", "url": "https://www.scielo.br/j/mr/a/kgNcGQ55wgqyJngcwjVm8Qk/?lang=en", "year": 2023 }, { "title": "USGS Mineral Commodity Summaries 2026: Nickel", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf", "year": 2026 }, { "title": "USGS Mineral Commodity Summaries 2026: Manganese", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-manganese.pdf", "year": 2026 }, { "title": "USGS Mineral Commodity Summaries 2026: Gallium", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gallium.pdf", "year": 2026 }, { "title": "Gallium safety data sheet (Angstrom Sciences, CAS 7440-55-3)", "type": "sds", "url": "https://angstromsciences.com/wp-content/uploads/files/SDS/Gallium.pdf" }, { "title": "Nickel Based Metal Alloys safety data sheet (Greenville Metals, PCC Forged Products)", "type": "sds", "url": "https://www.pccforgedproducts.com/documents/greenville/sds/nickel-based-metal-alloys-sds.pdf" } ], "gaps": [ "No density or elastic modulus for Ni-Mn-Ga was read in a source in this run. The Ni2MnGa searches returned no density, and the Vasil'ev and Khovailo papers give none.", "No corrosion, oxidation or ageing data for Ni-Mn-Ga was found, so the corrosion list is empty.", "No UNS, EN, JIS, AISI, ASTM or other designation for Ni-Mn-Ga was printed in a source read in this run, so designations is empty.", "No safety data sheet for the Ni-Mn-Ga alloy itself was read. The nickel-based alloy SDS (Greenville Metals) is a related product, not the same grade, and the Mn SDS was not read.", "The Wikipedia Ni-Mn-Ga page was not used for values. The Heusler and magnetic shape-memory Wikipedia pages are secondary and were read only for composition and history.", "The Springer review (s40830-024-00510-z) redirected to a sign-in page, and the PubChem gallium page returned a verification page, so no PubChem GHS entry was read.", "The Dubenko et al. 2012 abstract gives magnetic entropy change values for Ni-Mn-based Heusler alloys with In, Sn and Sb, not Ni-Mn-Ga, so none of its numbers were used.", "The full table of Materials Research 2023 (Batista et al.) was not read; only its abstract was, which gives compositions and phases but no property values.", "The Ni-Mn-Ga temperature range, fatigue life, output stress and cycling figures in the Wikipedia magnetic shape-memory page are secondary, and were not entered as values.", "No space-environment data (outgassing, atomic oxygen, radiation, thermal cycling in orbit) for Ni-Mn-Ga was found in a source read in this run.", "Critical-mineral list status for nickel, manganese and gallium was not confirmed: the USGS texts give no list, and the gallium text does not name one.", "Custom property names used because no canonical name exists: martensitic_transition_temperature, latent_heat_martensitic_transition, magnetic_field_induced_strain, magnetocrystalline_anisotropy_constant and magnetic_entropy_change.", "Table I values in the Vasil'ev review are from a 2003 review table and are cited to the original reference numbers, not re-measured here. The supply shares are calculated by Space Mushroom from printed tonnages." ], "story": { "why": "Ni-Mn-Ga is a ferromagnetic shape-memory alloy. Its martensite can be reoriented by a magnetic field, so it can change shape fast without a heating cycle. Single crystals show 5.1 to 7.3 % magnetically induced strain in one review table, and the Curie temperature of stoichiometric Ni2MnGa is about 370 K.", "uses": [ { "where": "Magnetic actuators", "line": "The 2000 MRS-J paper calls Ni-Mn-Ga a good candidate for magnetic actuator materials, and the 2003 review notes that actuators and sensors based on this class of alloy need more durability first." }, { "where": "Magnetocaloric cooling", "line": "A 2005 conference paper reports 9 J/kgK at 338 K and 11 J/kgK at 344 K in a 26 kOe field." } ], "can_do": [ { "label": "Change shape by field", "line": "Single crystals of Ni48 Mn31 Ga21, Ni49.8 Mn28.5 Ga21.7 and Ni48.2 Mn30.8 Ga21 gave 5.1, 6.0 and 7.3 % magnetically induced strain.", "scope": "material", "value": "5.1 to 7.3 %" }, { "label": "Work near room temperature", "line": "The Curie temperature of stoichiometric Ni2MnGa is about 370 K, and the transition temperature Tm of the series runs from 201 K to 342 K.", "scope": "material", "value": "201 to 342 K" }, { "label": "Cool by magnetic entropy change", "line": "A magnetic entropy change of 9 J/kgK at 338 K was measured in a 26 kOe field, and 11 J/kgK at 344 K when the field was removed.", "scope": "material", "value": "9 and 11 J/kgK" } ], "compare": "Among the Ni2+xMn1-xGa series, the martensitic transition temperature rises with nickel content, from 201 K at x = 0 to 342 K at x = 0.19, while the Curie temperature falls toward it. Strain values come from single crystals in one review table and from a nonmodulated single crystal in a 2009 paper, so they are not directly comparable with the table values.", "compare_rows": [ { "label": "Curie temperature", "benchmark": "curie_temperature", "scope": "material" }, { "label": "Martensitic transition temperature", "benchmark": "martensitic_transition_temperature", "scope": "material" }, { "label": "Magnetic field induced strain", "benchmark": "magnetic_field_induced_strain", "scope": "material" } ], "handling": [ "Homogenize the ingot at 1073 K for 48 to 72 hours under argon, then quench.", "Check the composition by EDX, since Tm moves with composition.", "Treat gallium as corrosive to metals (H290) and follow the supplier SDS." ], "good_for": [ "Single-crystal magnetic actuators where stroke is set by a field, with 5.1 to 7.3 % strain in one review table.", "Magnetocaloric refrigerant studies near room temperature, with 9 and 11 J/kgK entropy changes in a 26 kOe field." ], "watch_out": [ "Brittleness: the 2000 MRS-J paper names it as a main obstacle to practical use.", "Composition: Tm moves from 201 K to 342 K across the series.", "Cut position: a crystal cut from the middle of the boule gave no strain in the review.", "Hazards: the SDS codes used here come from a nickel alloy and gallium, not a Ni-Mn-Ga SDS." ], "verdict": "Ni-Mn-Ga is a magnetically driven shape-memory Heusler alloy. Its strain is set by a magnetic field, not by heat, and its single crystals gave 5.1 to 7.3 % strain in one review table. The record still lacks density, elastic modulus, corrosion data, a Ni-Mn-Ga SDS, designations and any space-environment data, so it is a draft.", "recipe": { "line": "Ni-Mn-Ga is made by argon arc melting of the three metals, followed by homogenization at 1073 K for 48 to 72 hours in argon and quenching into room-temperature water (Tsuchiya 2000). Composition is set by the Ni, Mn and Ga ratio, with stoichiometric Ni2MnGa as the reference.", "parts": [ { "name": "Nickel", "symbol": "Ni", "role": "Sets the transition temperature and Curie temperature; excess nickel raises Tm and lowers TC", "share_note": "2 of 4 formula positions in stoichiometric Ni2MnGa (x = 0), then Ni2+xMn1-xGa to x = 0.19", "source": "khovailo2004", "where": "Formula Ni2+xMn1-xGa, Introduction" }, { "name": "Manganese", "symbol": "Mn", "role": "Carries the magnetic moment of the Heusler lattice and sets the Mn-rich compositions with the largest strain", "share_note": "1 of 4 formula positions in stoichiometric Ni2MnGa (x = 0); lower in the Ni-rich series", "source": "khovailo2004", "where": "Formula Ni2+xMn1-xGa, Introduction" }, { "name": "Gallium", "symbol": "Ga", "role": "Heusler third element; its content is fixed by the Mn-Ni balance in the studied series", "share_note": "1 of 4 formula positions in stoichiometric Ni2MnGa (x = 0)", "source": "khovailo2004", "where": "Formula Ni2MnGa, Introduction" } ] }, "risk_groups": [ { "title": "For people", "lead": "Ni-Mn-Ga is a nickel alloy. The sources supplied here cover nickel-based alloy and gallium hazards, not a Ni-Mn-Ga supplier SDS.", "points": [ { "label": "Codes found", "line": "A nickel-based alloy SDS lists H317, H351, H372 and H410, and a gallium SDS lists H290, which may be corrosive to metals." }, { "label": "Gap", "line": "No safety data sheet for the Ni-Mn-Ga alloy itself was read in this run, so the codes above are a proxy." } ], "level": 2, "verdict": "Nickel and gallium hazards" }, { "title": "If it fails", "lead": "The sources name brittleness, composition shift and loss of strain as the main ways a Ni-Mn-Ga part stops working.", "points": [ { "label": "Brittleness", "line": "The 2000 MRS-J paper names inherent brittleness as one of the problems to overcome before practical use." }, { "label": "Composition drift", "line": "The martensitic transition temperature rises from 201 K at x = 0 to 342 K at x = 0.19, and the Curie temperature falls toward it." } ], "level": 2, "verdict": "Brittleness and composition" }, { "title": "Handling and storage", "points": [ { "label": "Melting", "line": "Ingots are arc melted under argon, homogenized at 1073 K for 48 to 72 hours, and quenched." }, { "label": "Sample position", "line": "A crystal cut from the middle of the boule gave no magnetically induced strain in the review, so cut position matters." } ] } ] }, "updated": "2026-10-26", "review": { "status": "draft", "method": "assistant", "checked_values": 19, "unreachable": 3, "caveats": 5, "note": "Values were read by an AI assistant on 2026-10-26 from the papers, reports and safety data sheets named in each entry. Unreachable: the Springer review (sign-in redirect), the PubChem gallium page (verification page), and the Sigma-Aldrich SDS (timeout). Caveats: the hazard codes come from a nickel-based alloy SDS, not a Ni-Mn-Ga SDS; the Table I values are from a 2003 review and cite original references; the magnetocaloric numbers come from a conference summary with no composition; the strain values are for single crystals and a nonmodulated crystal, not comparable; the supply shares are calculated." }, "sources": { "khovailo2004": { "title": "Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys (Khovailo et al., Phys. Rev. B 70, 174413, 2004)", "url": "https://arxiv.org/pdf/cond-mat/0405134", "year": 2004, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" }, "vasil2003": { "title": "Shape memory ferromagnets (Vasil'ev et al., arXiv cond-mat/0311433, 2003)", "url": "https://arxiv.org/pdf/cond-mat/0311433", "year": 2003, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" }, "chernenko2009": { "title": "Large Magnetic-Field-Induced Strains in Ni-Mn-Ga Nonmodulated Martensite (Chernenko, Chmielus, Mullner, Applied Physics Letters 95, 104103, 2009)", "url": "https://scholarworks.boisestate.edu/mse_facpubs/40", "year": 2009, "kind": "paper", "license": "author repository (cited, not reproduced)" }, "aliev2005": { "title": "Magnetocaloric effect in Ni-Mn-Ga Heusler alloys (Aliev et al., 1st International Conference on Magnetic Refrigeration at Room Temperature, 2005)", "url": "https://iifiir.org/en/fridoc/magnetocaloric-effect-in-ni-mn-ga-heusler-alloys-22416", "year": 2005, "kind": "paper", "license": "IIR document (cited, not reproduced)" }, "tsuchiya2000": { "title": "Effect of Fourth Elements on Phase Transformations in Ni-Mn-Ga Heusler Alloys (Tsuchiya et al., Trans. Mater. Res. Soc. Jpn. 25, 2000)", "url": "https://www.mrs-j.org/pub/tmrsj/vol25_no2/vol25_no2_517.pdf", "year": 2000, "kind": "paper", "license": "open access (cited, not reproduced)" }, "batista2023": { "title": "Structural, Thermal and Magnetic Characterization of Polycrystalline Ni-Mn-Ga Ferromagnetic Shape Memory Alloys (Batista et al., Materials Research 26, 2023)", "url": "https://www.scielo.br/j/mr/a/kgNcGQ55wgqyJngcwjVm8Qk/?lang=en", "year": 2023, "kind": "paper", "license": "open access (cited, not reproduced)" }, "wiki-msma": { "title": "Magnetic shape-memory alloy, Wikipedia (composition and history only)", "url": "https://en.wikipedia.org/wiki/Magnetic_shape-memory_alloy", "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" }, "usgs-ni": { "title": "Mineral Commodity Summaries 2026, Nickel (USGS, February 2026)", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "usgs-mn": { "title": "Mineral Commodity Summaries 2026, Manganese (USGS, February 2026)", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-manganese.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "usgs-ga": { "title": "Mineral Commodity Summaries 2026, Gallium (USGS, February 2026)", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gallium.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "sds-ga": { "title": "Gallium safety data sheet (Angstrom Sciences, CAS 7440-55-3)", "url": "https://angstromsciences.com/wp-content/uploads/files/SDS/Gallium.pdf", "kind": "datasheet", "license": "manufacturer safety data sheet (cited, not reproduced)" }, "sds-ni-alloy": { "title": "Nickel Based Metal Alloys safety data sheet (Greenville Metals, PCC Forged Products)", "url": "https://www.pccforgedproducts.com/documents/greenville/sds/nickel-based-metal-alloys-sds.pdf", "kind": "datasheet", "license": "manufacturer safety data sheet (cited, not reproduced)" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/nimnga-shape-memory/" }