A.G. Gamzatov, A. B. Batdalov, Sh. K. Khizriev, A. M. Mukhuchev, A. M. Aliev, A. Ghotbi Varzaneh, P. Kameli, I. Abdolhosseini Sarsari, S. Jannati, “Heat capacity, thermal conductivity and magnetocaloric effect in Heusler alloy Ni$_{47}$Mn$_{40}$Sn$_{13}$”, Fizika Tverdogo Tela, 2022, Volume 64, Issue 12,Pages 2094

Thermal properties

Heat capacity, thermal conductivity and magnetocaloric effect in Heusler alloy Ni$_{47}$Mn$_{40}$Sn$_{13}$

A.G. Gamzatov^a, A. B. Batdalov^a, Sh. K. Khizriev^a, A. M. Mukhuchev^a, A. M. Aliev^a, A. Ghotbi Varzaneh^b, P. Kameli^b, I. Abdolhosseini Sarsari^b, S. Jannati^b

^a Daghestan Institute of Physics after Amirkhanov, Makhachkala, Russia
^b Department of Physics, Isfahan University of Technology, Isfahan 8415683111, Iran

Abstract: The results of a study of heat capacity, thermal conductivity and magnetocaloric effect of the polycrystalline Ni$_{47}$Mn$_{40}$Sn$_{13}$ alloy depending on temperature ($T$ = 80–350 K) and magnetic field (0–8 T) are given. A considerable difference between the values of a sudden change in heat capacity $\Delta C_P$ in the heating and cooling mode was found near the magnetostructural martensite-austenite phase transition (MSPT), which is related to influence of latent heat of phase transition. Thermal conductivity in the range of $T$ = 80–300 K rises with temperature $(d\kappa/dT>0)$ and increases in more than three times. Electronic thermal conductivity in the martensitic phase ($T$ = 150 K) is 37% of the total value. An anomalous rise of thermal conductivity $\Delta\kappa=\kappa(аust)-\kappa(mart)$ = 4.2 Wm K was found in the region of MSPT. The contributions of electrons and phonons to the observed sudden change are 63 and 37% respectively and are conditioned both by a rise of mobility of conduction electrons under a martensite-austenite transition and by an increase of phonons' free path length.
The magnetocaloric effect in cyclic magnetic fields with the amplitude of 1.8 T was studied. A dependence of reverse effect value on temperature scanning rate was established. The direct measurements of $\Delta T$ in the cyclic magnetic field of 1.2 T show a twofold decrease of the effect amplitude near $T_C$ at an increase of cyclic magnetic field frequency from 1 to 30 Hz. Most likely, this is related to magnetic and microstructural heterogeneities which act as an additional thermal dissipation channel.

Keywords: Heusler alloys, heat capacity, thermal conductivity, magnetocaloric effect, cyclic magnetic fields.

Received: 28.09.2022
Revised: 28.09.2022
Accepted: 29.09.2022

DOI: 10.21883/FTT.2022.12.53714.487