Abstract:
Thermal conductivity $(\kappa)$, heat capacity $(C_{\mathrm{P}})$, magnetization $(M)$ and electrical resistivity $(\rho)$ of the Ni$_{50.2}$Mn$_{39.8}$In$_{10}$ Heusler alloy were measured in wide temperature range of $T$ = 25–350 K. Anomalies were found on the $M(T)$ and $C_{\mathrm{P}}(T)$ curves, indicating phase transitions of the second and first order with the Curie temperature $T_{\mathrm{C}}$ = 322 K and the temperature of the martensitic transition start $M_{\mathrm{S}}$ = 296 K. A sharp increase in thermal conductivity $\Delta\kappa$ = 3.2 W/(m $\cdot$ K) during the martensite-austenite transition is found, caused by the electron contribution due to the electron mobility increasing during the transition to the more symmetric phase. The lattice thermal conductivity changes insignificantly during the transition, that indicates the insensitivity of phonons to the structural disorder.
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