Effect of Magnetic Field and Hydrostatic Pressure on Metamagnetic Isostructural Phase Transition and Multicaloric Response of Fe49Rh51 Alloy

Abstract

The effect of a high magnetic field up to 12 T and a high hydrostatic pressure up to 12 kbar on the stability of the metamagnetic isostructural phase transition and the multicaloric effect of Fe49Rh51 alloy has been studied. The phase transition temperature shifts under the magnetic field and the hydrostatic pressure on with the rates of dTm/μ0dH = −9.2 K/T and dTm/dP = 3.4 K/kbar, respectively. The magnetocaloric and multicaloric (under two external fields) effects were studied via indirect method using Maxwell relations. The maximum of the entropy change is increasing toward the high temperature region from ∆S~2.5 J/(kg K) at 305 K to ∆S~2.7 J/(kg K) at 344 K under simultaneously applied magnetic field of 0.97 T and hydrostatic pressure of 12 kbar. The obtained results were explained using the first-principle calculations of Gibbs energies and the phonon spectra of the ferromagnetic and the antiferromagnetic phases. Taking into account the low concentration of antisite defects in the calculation cells allows us to reproduce the experimental dTm/dP coefficient.

Flexible Magnetocaloric Fiber Mats for Room-Temperature Energy Applications

“…Furthermore, the smart design of magnetocaloric materials with functional polymers enables the development of multifunctional composites exhibiting large responses to different external stimuli (including magnetic, electric, and pressure fields) and cross-coupling effects, such as magnetoelectric coupling in multiple systems. − Within the context of caloric applications, these systems are known as multicaloric composites. ,− The application of multicaloric materials in prototype devices has already enabled reaching higher cooling power and efficiency . A prime example of the latter is the multicaloric heat pump design proposed by Gottschall et al that makes use of the barocaloric and magnetocaloric effects by applying/removing uniaxial stress and magnetic fields, respectively, in such a way that hysteresis is further exploited …”

“… 33 − 35 Within the context of caloric applications, these systems are known as multicaloric composites. 34 , 36 − 38 The application of multicaloric materials in prototype devices has already enabled reaching higher cooling power 39 and efficiency. 40 A prime example of the latter is the multicaloric heat pump design proposed by Gottschall et al that makes use of the barocaloric and magnetocaloric effects by applying/removing uniaxial stress and magnetic fields, respectively, in such a way that hysteresis is further exploited.…”