Seminarium Międzynarodowego Laboratorium Silnych Pól Magnetycznych i Niskich Temperatur PAN

Direct in situ study of magnetocaloric effect and martensitic twins structure of heusler alloy in high magnetic fields up to 14 T

dr Yuri Koshkid’ko

The study of the materials with high magnetocaloric effect (MCE) is of a great interest in view of prospects of the development of a new solid state technology of magnetic refrigeration. In addition, research of MCE is very attractive in order to obtain new important information about fundamental aspects of magnetic phase transitions and subsystems interaction in magnetically orders solids. In general, at magnetic phase transition of the first order MCE, values measured by indirect methods can differ substantially  from the values got by the direct ones [1]. In order to look into this issue, we have developed a new technique for in situ study of MCE by direct method in adiabatic or isothermal regimes simultaneously with optical observation of martensitic domains evolution of the substance with magnetostructural transition in the field of Bitter coil up to 14 T. Heusler alloy was selected for the experiments [2]. The experimental results are compared with results of the thermodynamic model treatment.

[1] Khovaylo, V.V., Skokov, K.P., Koshkid'ko, Yu.S. et al. Phys. Rev. B  78, 060403 (2008).
[2] Kamantsev A. P., Koshkid'ko Yu. S., Cwik J. et al. J. Appl. Phys. 117, 163903 (2015).