Observation of inverse magnetocaloric effect in magnetic-field-induced austenite phase of Heusler alloys <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Ni</mml:mi><mml:mrow><mml:mn>50</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>Co</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi>Mn</mml:mi><mml:mrow><mml:mn>31.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi>Ga</mml:mi><mml:mrow><mml:mn>18.5</mml:mn></mml:mrow…

Magnetocaloric effect (MCE), magnetization, specific heat, and magnetostriction measurements were performed in both pulsed steady high magnetic fields to investigate the magnetocaloric properties of Heusler alloys Ni50-xCoxMn31.5Ga18.5 (x = 9 9.7). From direct MCE for Ni41Co9Mn31.5Ga18.5 up 56 T, a steep temperature drop was observed magnetic-field-induced martensitic transformation (MFIMT), designated as inverse MCE. Remarkably, this is apparent not only with MFIMT, but also austenite phase. Specific heat under revealed that field variation electronic entropy plays dominant role unconventional these materials. First-principles based calculations Ni45Co5Mn36.7In13.3 phase more unstable than it sensitive slight tetragonal distortion. We conclude realized by marked change through distortion induced externally applied field.