Reliable thermodynamic estimators for screening caloric materials

JOURNAL OF ALLOYS AND COMPOUNDS

卷:802

Article

Zarkevich, Nikolai A.¹  Johnson, Duane D.^1,2 

[1] US DOE, Ames Lab, Ames, IA 50011 USA

[2] Iowa State Univ, Mat Sci & Engn, Ames, IA 50011 USA

关键词: caloric;    Thermodynamic;    Metamagnetic;    Phase transformation;    FeRh;   

DOI  :  10.1016/j.jallcom.2019.06.150

来源: Elsevier

【 摘 要 】

Reversible, diffusionless, first-order solid-solid phase transitions accompanied by caloric effects are critical for applications in the solid-state cooling and heat-pumping devices. Accelerated discovery of caloric materials requires reliable but faster estimators for predictions and high-throughput screening of system-specific dominant caloric contributions. We assess reliability of the computational methods that provide thermodynamic properties in relevant solid phases at or near a phase transition. We test the methods using the well-studied B2 FeRh alloy as a fruit fly in such a materials genome discovery, as it exhibits a metamagnetic transition which generates multicaloric (magneto-, elasto-, and baro-caloric) responses. For lattice entropy contributions, we find that the commonly-used linear-response and small-displacement phonon methods are invalid near instabilities that arise from the anharmonicity of atomic potentials, and we offer a more reliable and precise method for calculating lattice entropy at a fixed temperature. Then, we apply a set of reliable methods and estimators to the metamagnetic transition in FeRh (predicted 346 +/- 12 K, observed 353 +/- 1 K) and calculate the associated caloric properties, such as isothermal entropy and isentropic temperature changes. (C) 2019 Elsevier B.V. All rights reserved.

【 授权许可】

Free