Phase transitions in intermetallic compounds Ni-Mn-Ga with shape memory effect

摘要

The effect of a magnetic field on the formation of structural domains at martensitic transition in the intermetallic system Ni/sub 2+x/Mn/sub 1-x/Ga was studied. For the compositions x whose temperatures of structural and magnetic transitions are close this effect is most pronounced. In the field of 0.2 to 1 T the increase in the transition temperature is linear with the coefficient of 0.015 K/T. Estimates of the transition temperature shift based on thermodynamic calculations are in good agreement with the experimental data. It is shown that the switching on the magnetic field at some critical temperature induces partial transformation of austenite into martensite.