Low-temperature Hall effect and martensitic transition temperatures in magnetocaloric Ni50Mn35Sb15–xGex(x = 0, 1, 3) alloys
V. V. Marchenkov1, 2 and S. M. Emelyanova1
1M. N. Mikheev Institute of Metal Physics of the Ural Branch of the Russian Academy of ScienceEkaterinburg 620108, Russia
2Ural Federal University, Ekaterinburg 620002, Russia
Received September 23, 2020, published online November 24, 2020
The field dependence of Hall resistivity ρH and magnetization M of the magnetocaloric Ni50Mn35Sb15–xGex(x = 0, 1, 3) alloys were measured at T = 4.2 K and in magnetic fields of up to 70 kOe. The martensitic transitions temperatures, i.e., the martensite start temperature MS, martensite finish temperature MF, austenite start AS and austenite finish AF temperatures, were obtained from the magnetization temperature dependence that measuredfrom 4.2 to 350 K in a field of 1 kOe. It was observed that the martensitic transitions temperatures correlate strongly both with the valence electron concentration e/a and with the electronic transport characteristics, which are the coefficients of normal R0 and anomalous RS Hall effect and the concentration of charge carriers n. Apparently, similar correlations should be observed in other magnetocaloric compounds that could be used to study martensitic transitions.
Key words: magnetocaloric Heusler alloys, Hall effect, normal and anomalous Hall coefficients, valence electron concentration, concentration of charge carriers.