Abstract
Here, we study the effect of external pressure on martensitic transition, magnetic, and magnetocaloric properties of Mn-rich Heusler alloys by using a combined experimental and first principles simulation. The alloy exhibits martensitic transition around room temperature (RT), which increases appreciably under external pressure for both the alloys. External pressure and magnetic field show opposite effects on martensitic transition . The alloy shows a maximum isothermal magnetic entropy change of 6.5 J/kg under ambient pressure at RT, which is comparatively larger than that reported in many other Heusler systems at RT. Interestingly, decreases with pressure for , while it shows an increasing trend for . A maximum refrigeration capacity of around is observed for . Similar to the magnetic entropy change, the net magnetization for and show opposite trend under external pressure. This is explained by our ab initio simulation by closely inspecting the consequence of nonuniform strain along three crystallographic directions on the net magnetization. This actually arises due to considerable magnetocrystalline anisotropy in these alloys. The unconventional mechanism behind the influence of pressure on magnetic properties is also discussed in the light of varying bond lengths between different magnetic species, and hence on the antiferromagnetic/ferromagnetic exchange coupling strengths under pressure.
1 More- Received 26 November 2023
- Revised 5 February 2024
- Accepted 7 February 2024
DOI:https://doi.org/10.1103/PhysRevB.109.064418
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