Martensitic Transformation Temperatures and Hall Effect in Ni_47-xMn_41+xIn₁₂ (x=0, 1, 2) Alloys

At present, the question of the relationship between the characteristic martensitic transformation temperatures (MTT) and the electronic parameters of a system has not been fully studied. In the present work, an attempt to establish a similar relationship using the example of the concentration of charge carriers, n, was made. The field dependences of Hall resistivity rho(H) and magnetization M of the magnetocaloric Ni47-xMn41+xIn12 (x = 0, 1, 2) alloys were measured at T = 4.2 K and in magnetic fields of up to 80 kOe. The MTT were obtained from the temperature dependences of electrical resistivity and magnetization. It was observed that the MTT correlate strongly with both the valence electron concentration e/a and the electronic transport characteristics, which are the coefficient of the normal (NHE) R-0 and anomalous (AHE) R-S Hall effect and the concentration of charge carriers n.