Magnetic properties and magnetocaloric effects of Tm_1–x Er _x CuAl (x = 0.25, 0.5, and 0.75) compounds

Abstract

The structural, magnetic, and magnetocaloric effects (MCE) of Tm1-x Er x CuAl (x = 0.25, 0.5, and 0.75) compounds were investigated. The compounds undergo a second-order phase transition originating from the ferromagnetic to paramagnetic transition around 3.2 K, 5 K and 6 K, respectively. The maximum magnetic entropy change (-ΔS M max of Tm1-x Er x CuAl (x = 0.25, 0.5, and 0.75) are 17.1 J kg-1K-1, 18.1 J kg-1K-1, and 17.5 J kg-1K-1 under the magnetic field change of 0-2 T, with corresponding RC of 131 J kg-1, 136 J kg-1 and 126 J kg-1, respectively. The increase of -ΔS M max for Tm0.5Er0.5CuAl may be relevant to the change of magnetic moment distribution of Er and stress coming from element substitution. This work has provided several compounds that enrich the family of giant MCE materials in the cryogenic region.

Advanced Magnetocaloric Materials for Energy Conversion: Recent Progress, Opportunities, and Perspective

“…In the past 2 decades, numerous first‐order magnetic transition (FOMT) plus strong second‐order magnetic transition (SOMT) MCMs that demonstrate a GMCE have sprung up, including Gd 5 (Si 2 Ge 2 ), [ 10 ] (Mn,Fe) 2 (P, X )‐based compounds ( X = As, Ge, Si), [ 11 ] La(Fe,Si) 13 ‐based materials, [ 12,29 ] NiMn‐ X based magnetic Heusler compounds ( X = Ga, In, Sn, Sb) [ 30 ] with as a special case the so‐called all‐ d ‐metal NiCoMnTi, [ 122 ] FeRh, [ 123 ] Mn 2 Sb based alloys, [ 124 ] Mn‐ M ‐ X ( M = Co, Ni and X = Si, Ge) alloys [ 32,33 ] and magnetocaloric high‐entropy alloys (MHEAs). [ 125 ] These materials demonstrate a strong FOMT with a discontinuous change in the first derivative of the Gibbs free energy resulting from the coupling between the magnetic and crystal lattice degrees of freedom in the form of a magnetoelastic (ME) or magnetostructural (MS) coupling.…”

“…As an intrinsic property of all magnetic materials, the MCE is the physical phenomenon where a magnetic material is heated or cooled when an external magnetic field is applied or removed. [ 8,9 ] Based on this effect, several promising potential applications, such as magnetic refrigeration (cooling), [ 10–12 ] magnetocaloric heat pumps (cooling/heating), [ 13 ] and thermomagnetic generators for harvesting waste heat [ 14,15 ] have been proposed and further developed. Amongst these applications, the magnetic refrigeration technique has a relatively long history as it was first demonstrated almost 100 years ago.…”

“…More historical details related to the MCE and room‐temperature magnetic cooling can be found in. [ 27,28 ] Numerous FOMT magnetocaloric materials (MCMs) that demonstrate a GMCE have sprung up, including (Mn,Fe) 2 (P, X )‐based compounds ( X = As, Ge, Si), [ 11 ] La(Fe,Si) 13 ‐based materials, [ 12,29 ] Ni‐Mn‐ X‐ based magnetic Heusler compounds ( X = Ga, In, Sn, Sb) [ 30,31 ] and Mn‐ M ‐ X ( M = Co, Ni and X = Si, Ge) compounds. [ 32,33 ] In the last 25 years a continuously growing interest has resulted in growing efforts to search for MCMs with a FOMT.…”

Spontaneous Topological (Anti)meron Chains in the Domain Walls of Centrosymmetric Rare‐Earth Magnet

“…As the temperature decreased below 176 K, the magnetization of the Tb atoms aligned along the c-axis. [43,46] To conduct a comprehensive study of the magnetic interactions in the Tb─Co─Si magnet, the density of states (DOSs) of the Tb 1 and Tb 2 atoms were calculated using first-principles calculations based on the ab initio calculations, as shown in Figure 1e. The asymmetric spin-up and spin-down for the Tb 1 and Tb 2 atoms indicate the dominance of the magnetic exchange of the Tb atoms in the Tb─Co─Si magnet.…”