Giant magnetocaloric effect in isostructural MnNiGe-CoNiGe system by establishing a Curie-temperature window

TL;DR

This paper demonstrates a giant magnetocaloric effect in an isostructural MnNiGe-CoNiGe system by establishing a Curie-temperature window through alloying, enabling potential magnetic refrigeration applications.

Contribution

It introduces a novel alloying scheme to create a Curie-temperature window in MnNiGe-CoNiGe, leading to a significant magnetocaloric effect.

Findings

Achieved a 200 K Curie-temperature window between phases.

Observed a magnetic entropy change of -40 J kg-1 K-1.

Demonstrated potential for magnetic refrigeration applications.

Abstract

An effective scheme of isostructural alloying was applied to establish a Curie-temperature window in isostructural MnNiGe-CoNiGe system. With the simultaneous accomplishment of decreasing structural-transition temperature and converting antiferromagnetic martensite to ferromagnetic state, a 200 K Curie-temperature window was established between Curie temperatures of austenite and martensite phases. In the window, a first-order magnetostructural transition between paramagnetic austenite and ferromagnetic martensite occurs with a sharp jump in magnetization, showing a magnetic entropy change as large as -40 J kg-1 K-1 in a 50 kOe field change. This giant magnetocaloric effect enables Mn1-xCoxNiGe to become a potential magnetic refrigerant.