Effect of chemical and external hydrostatic pressure on magnetic and magnetocaloric properties of Pt doped Ni2MnGa shape memory Heusler alloys

•The magnetic and magnetocaloric property is investigated for Pt doped Ni2−xPtxMnGa (x = 0.2, 0.3 and 1.0) alloys at ambient pressure.•The pressure also induces the AFM/FM interaction at low temperature for x = 0.2 alloy, where previously not observed in Ni-Mn based alloys under pressure.•The metama...

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Bibliographic Details
Published in:Journal of magnetism and magnetic materials 2020-11, Vol.514, p.167136, Article 167136
Main Authors: Sivaprakash, P., Esakki Muthu, S., Singh, Anupam K., Dubey, K.K., Kannan, M., Muthukumaran, S., Guha, Shampa, Kar, Manoranjan, Singh, Sanjay, Arumugam, S.
Format: Article
Language:English
Subjects:
Entropy
External pressure
Heusler alloys
Hydrostatic pressure
Magnetic properties
Magnetocaloric effect
Martensite
Martensite transition
Martensitic transformations
Phase transitions
Platinum
Pressure effects
Shape Memory alloys
Transition temperature
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Summary:•The magnetic and magnetocaloric property is investigated for Pt doped Ni2−xPtxMnGa (x = 0.2, 0.3 and 1.0) alloys at ambient pressure.•The pressure also induces the AFM/FM interaction at low temperature for x = 0.2 alloy, where previously not observed in Ni-Mn based alloys under pressure.•The metamagnetic transition and crossover of magnetization are suppressed for x = 1.0 alloy.•The application of chemical and hydrostatic pressure increases the TM and decreases ΔSM. The magnetocaloric effect (MCE) on Ni2−xPtxMnGa (x = 0.2, 0.3 and 1.0) shape memory Heusler alloys around martensite phase transition temperature (TM) is investigated by varying chemical pressure (Pt concentration). The magnetic entropy change (ΔSM) decreases with increasing chemical pressure for various external applied magnetic fields up to 3 T, and the width of thermal hysteresis increases with the increases of Pt concentration. The effect of hydrostatic pressure on both TM and ΔSM for Ni1.8Pt0.2MnGa is also investigated. We observed that the application of hydrostatic pressure increases TM (3.5 K/GPa) and stabilizes the martensite phase. The maximum magnetic entropy change (ΔSmax) of 9.31 J Kg−1 K-1is observed for a field change of 9 T at ambient pressure for Ni1.8Pt0.2MnGa. Further, the application of external pressure leads to the decrease of ΔSmax to 5.52 J Kg−1 K−1 at 0.91 GPa.
ISSN:0304-8853
1873-4766
DOI:10.1016/j.jmmm.2020.167136