Cherechukin A.A., Koledov V.V., Shavrov V.G., Tulaikova A.A., Vasil'ev A.N. Magnetic and structural phase transitions in Ni2+УMn1-УGa (0<У<1) alloys are investigated experimentally. The martensite domains formation under the action of external magnetic field on the surface of polycrystalline Ni2,19Mn0,81Ga specimen was investigated by optical method. ... It is found that the martensite phase formation temperature is enhanced by the order of 0,3 K in magnetic field of 1 kOe. ...