Hydrostatic pressure induced giant enhancement of entropy change as driven by structural transition in Mn0.9Fe0.2Ni0.9Ge0.93Si0.07

The magnetostructural transition (MST) can be tuned close to room temperature for an isostructurally alloyed (MnNiGe)(1-x)(Fe2Ge)(x) (x=0.1) compound by partially substituting a small amount of Si for Ge (7at.%). In this study, the effect of hydrostatic pressure (p) on MST is investigated. In comparison to purely magnetically induced phase transition, pressure initiates structural transition more abruptly, which results in an increase in the isothermal entropy change by a factor of 2 from -Delta s=25.6 (p=0) to 45.6J/kg K (p=190MPa) for a magnetic field change of 2T. Since the direct assessment of the adiabatic temperature change, Delta T-ad, is difficult due to the large volume change and subsequent structural breakdown at MST, an indirect method has been employed to estimate Delta T-ad.

Automated summary

This study investigated the effect of hydrostatic pressure on the magnetostructural transition (MST) in an isostructurally alloyed compound, and found that pressure can induce a structural transition more abruptly than purely magnetically induced phase transition, leading to an increase in isothermal entropy change drastically. Due to the large volume change and structural breakdown at MST, an indirect method was used to estimate adiabatic temperature change.