Giant magnetocaloric effect driven by first-order magneto-structural transition in cosubstituted Ni-Mn-Sb Heusler compounds: predictions from \textit{Ab initio} and Monte Carlo calculations

TL;DR

This paper presents a computational approach combining Density Functional Theory and thermodynamic modeling to predict new Heusler compounds with giant magnetocaloric effects driven by first-order magneto-structural transitions, validated through predictions of improved thermodynamic parameters.

Contribution

It introduces a systematic screening protocol for Heusler compounds using ab initio and Monte Carlo calculations, enabling the prediction of materials with enhanced magnetocaloric properties through cosubstitution.

Findings

Predicted four new compounds with potential giant magnetocaloric effects.

Thermodynamic parameters improved up to four times compared to existing materials.

Established a protocol for selecting and tuning Heusler compounds for magnetocaloric applications.

Abstract

Using Density Functional Theory and a thermodynamic model [Physical Review B 86, 134418 (2012)], in this paper, we provide an approach to systematically screen compounds of a given Heusler family to predict ones that can yield giant magnetocaloric effect driven by a first-order magneto-structural transition. We apply this approach to two Heusler series Ni$_{2-x}$Fe$_{x}$Mn$_{1+z-y}$Cu$_{y}$Sb$_{1-z}$ and Ni$_{2-x}$Co$_{x}$Mn$_{1+z-y}$Cu$_{y}$Sb$_{1-z}$, obtained by cosubstitution at Ni and Mn sites. We predict four new compounds with potentials to achieve the target properties. Our computations of the thermodynamic parameters, relevant for magnetocaloric applications, show that the improvement in the parameters in the predicted cosubstituted compounds can be as large as four times in comparison to the off-stoichiometric Ni-Mn-Sb and a compound derived by single substitution at the Ni site, where magnetocaloric effects have been observed experimentally. This work establishes a protocol to select new compounds that can exhibit large magnetocaloric effects and demonstrate cosubstitution as a route for more flexible tuneability to achieve outcomes, better than the existing ones.