Origin and tuning of the magnetocaloric effect for the magnetic refrigerant MnFe(P1-xGex)

TL;DR

This study investigates the origin and tuning of the magnetocaloric effect in MnFe(P1-xGex), demonstrating that phase control can significantly enhance magnetic entropy change, surpassing previous records.

Contribution

The paper reveals how phase fraction control in MnFe(P1-xGex) influences the magnetocaloric effect, achieving record-high entropy change values.

Findings

Maximum magnetic entropy change exceeds 74 J/Kg K

Distinct crystal structures for ferromagnetic and paramagnetic phases

Phase fraction tuning enhances magnetocaloric performance

Abstract

Neutron diffraction and magnetization measurements of the magneto refrigerant Mn1+yFe1-yP1-xGex reveal that the ferromagnetic and paramagnetic phases correspond to two very distinct crystal structures, with the magnetic entropy change as a function of magnetic field or temperature being directly controlled by the phase fraction of this first-order transition. By tuning the physical properties of this system we have achieved a maximum magnetic entropy change exceeding 74 J/Kg K for both increasing and decreasing field, more than twice the value of the previous record.