Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 5: Heusler compounds, semimetals and oxides (joint session MA/TT)
MA 5.8: Vortrag
Montag, 12. März 2018, 11:30–11:45, EB 301
Improved reversibility by hydrostatic pressure in Ni-Mn based Heusler alloys — •Parul Devi1, Luana Caron1, Sanjay Singh1, Alexandre Magnuu G. Carvalho2, and Claudia Felser1 — 1Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — 2Laboratório Nacional de Luz Síncrotron, SáoPaulo, Brasil
Ni-Mn based Heusler alloys show first order diffusionless magnetostructural phase transition. The first order magnetostructural phase transition results in large magnetocaloric effect due to the change in both magnetic and crystal structure. The thermal or magnetic hysteresis is characteristic of first order phase transition which results in irreversibility of MCE. This irreversibility makes these materials less efficient for magnetic refrigeration. Therefore, nowadays, a lot of efforts have been made to reduce the hysteresis in these alloys [1].
In the present work, we observed a large reduction of hysteresis in off stoichiometric composition of Ni-Mn-In by hydrostatic pressure. To confirm that it is applicable to all Heusler alloys, we did it for two more different compositions of Ni-Mn based Heusler alloys. We got the decrement of hysteresis in these materials as well. However the rate of decrease in all three materials were different. Furthermore, we confirmed that the decrease in hysteresis was because of the increasingly geometric compatibility condition, recently predicted by James and co-workers [2].
[1]J. Liu et al., Nature materials 11, 620 (2012).
[2]Y. Song et al., Nature Letter 502, 85 (2013).