与GdGaTeO相比，GdFeTeO中的手性与磁热效应

Chirality and Magnetocaloricity in GdFeTeO as Compared to GdGaTeO.

作者信息

Zvereva Elena, Vasilchikova Tatyana, Evstigneeva Maria, Tyureva Angelica, Nalbandyan Vladimir, Gonçalves João, Barone Paolo, Stroppa Alessandro, Vasiliev Alexander

机构信息

Department of Low Temperature Physics and Superconductivity, Physics Faculty, Lomonosov Moscow State University, 119991 Moscow, Russia.

Department of Chemistry, Southern Federal University, 344090 Rostov-on-Don, Russia.

出版信息

Materials (Basel). 2021 Oct 10;14(20):5954. doi: 10.3390/ma14205954.

DOI:10.3390/ma14205954

PMID:34683545

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8539160/

Abstract

GdFeTeO and GdGaTeO have been prepared and their structures refined by the Rietveld method. Both are superstructures of the rosiaite type (space group P3¯1c). Their thermodynamic properties have been investigated by means of magnetization and specific heat measurements, evidencing the formation of the long-range antiferromagnetic order at = 2.4 K in the former compound and paramagnetic behavior down to 2 K in the latter compound. Large magnetocaloric effect allows considering GdFeTeO for the magnetic refrigeration at liquid hydrogen stage. Density functional theory calculations produce estimations of leading Gd-Gd, Gd-Fe and Fe-Fe interactions suggesting unique chiral 120° magnetic structure of Fe ( = 5/2) moments and Gd ( = 7/2) moments rotating in opposite directions (clockwise/anticlockwise) within weakly coupled layers of the rosiaite type crystal structure.

摘要

已制备出GdFeTeO和GdGaTeO，并通过Rietveld方法对其结构进行了精修。二者均为蔷薇辉石型的超结构（空间群P3¯1c）。通过磁化强度和比热测量研究了它们的热力学性质，结果表明，前一种化合物在2.4 K时形成了长程反铁磁序，而后一种化合物在2 K以下表现为顺磁行为。大的磁热效应使得GdFeTeO有望用于液氢阶段的磁制冷。密度泛函理论计算对主要的Gd-Gd、Gd-Fe和Fe-Fe相互作用进行了估算，表明在蔷薇辉石型晶体结构的弱耦合层内，Fe（S = 5/2）磁矩和Gd（S = 7/2）磁矩具有独特的手性120°磁结构，且二者沿相反方向（顺时针/逆时针）旋转。