Intermartensitic transformation and magnetic field effect in NiMnInSb ferromagnetic shape memory alloys

Partially substituting Sb for In, we found an irreversible transformation of martensite to intermartensite at 90 K in Ni₅₀Mn₃₄In₁₂Sb₄ alloy during heating. The reverse transformation of martensite and intermartensite to the parent phase induced by a magnetic field has been investigated. The results indicate that, if a sufficiently high magnetic field is applied, the intermartensite state is no longer necessary as an intermediate state. Thus, a difference of the transformation originating from magnetic and from thermal energies has been found. In this competition, lattice distortions play an important role to promote the occurrence of the intermediate intermartensitic path.