Electrical transport and thermal properties of ferromagnetic shape memory alloy Ni49.4Mn30Ga20.6

The electrical transport and thermal properties of the ferromagnetic shape memory alloy Ni49.4Mn30Ga20.6 are measured. Near around the starting point from austenite to martensite transition, the temperature (T) dependence of resistance for the sample shows a clear jump due to a great scattering mechanism introduced by the transformation resulting in many interfaces during the process. T-dependent curve of the thermoelectric power (S) of the sample shows linear dependence below martensitic transformation temperature with its absolute value decreasing during cooling. The absolute value of S tends to reach at a maximum at the martensitic transformation which is reflected by ∂S/∂T∼0. This may be related to the changes of the density of states near the phase transformation and the corresponding scattering introduced.