吉帕级单轴应力下Mn_(3)Sn单晶的磁化率增强  

Enhancement of magnetic susceptibility of Mn_(3)Sn single crystal under GPa-level uniaxial stress

作　　者：邓珊珊 宋平 刘潇贺 姚森 赵谦毅 Deng Shan-Shan;Song Ping;Liu Xiao-He;Yao Sen;Zhao Qian-Yi(State Key Laboratory of Metastable Materials Science&Technology,Key Laboratory for Microstructural Material Physics of Hebei Province,School of Science,Yanshan University,Qinhuangdao 066000,China)

机构地区：[1]燕山大学理学院,亚稳材料制备技术与科学国家重点实验室,河北省微结构材料物理重点实验室,秦皇岛066000

出　　处：《物理学报》2024年第12期359-366,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:52101233,51931007,U22A20116,52071279,52101234,52371200);河北省自然科学基金(批准号:E2022203010);河北省创新能力提升工程(批准号:22567605H)资助的课题。

摘　　要：如何在室温下实现非共线反铁磁Mn_(3)Sn自旋的调控是一项挑战.本文通过对Mn_(3)Sn单晶施加GPa级单轴应力调控其磁结构,发现随着应力的增大,晶格常数a逐渐减小.此外,GPa级单轴应力下Mn_(3)Sn的磁化率(χ)不同于MPa级单轴应力下的结果,其值不再是一个定值,而是随着应力的增大而增大.当沿[1120]方向施加1.12 GPa应力后,χ达到0.0203μB/(f.u.T);当沿[0110]方向施加1.11 GPa应力后,χ达到0.0332μB/(f.u.T),为未变形样品的2.4倍.进一步的实验结果表明,GPa级的单轴应力打破了kagome晶格的面内六边形的对称性,从而改变Mn原子间的交换相互作用,增强体系的反铁磁耦合作用,使χ不再是一个定值.这一发现将会为反铁磁自旋调控提供新的思路.How to achieve spin control of noncollinear antiferromagnetic Mn3Sn at room temperature is a challenge.In this study,we modulate the magnetic structure of Mn3Sn single crystals by subjecting them to uniaxial stress at the GPa level using a high-pressure combined deformation method.Initially,the single crystal is sliced into regular cuboids,then embedded in a stainless steel sleeve,and finally,uniaxial stress is applied along the[1120]direction and[0110]direction of the Mn3Sn single crystal.Under high stress,the single crystal undergoes plastic deformation.Our observations reveal lattice distortion in the deformed single crystal,with the lattice parameter gradually decreasing as the stress level increases.In addition,the magnetic susceptibility of Mn3Sn under GPa uniaxial stress(χ)is different from that under MPa uniaxial stress,and its value is no longer fixed but increases with the increase of stress.When 1.12 GPa stress is applied in the[1120]direction,χ reaches 0.0203μB·f.u.^(-1)·T^(-1),which is 1.42 times that of the undeformed sample.In the case of stress applied along the[011¯0]direction,χ≈0.0332μB·f.u.^(-1)·T^(-1) when the stress is 1.11 GPa.This result is also 2.66 times greater than the reported results.We further calculate the values of trimerization parameter(ξ),isotropic Heisenberg exchange interaction(J),and anisotropic energy(δ)of the system under different stresses.Our results show that ξ gradually increases,J gradually decreases,and δ gradually increases with the increase of stress.These results show that the GPa uniaxial stress introduces anisotropic strain energy into the single crystal,breaking the symmetry of the in-plane hexagon of the kagome lattice,which causes the bond length of the two equilateral triangles composed of Mn atoms to change.Thus,the exchange coupling between Mn atoms in the system is affected,the anisotropy of the system is enhanced,and the antiferromagnetic coupling of the system is enhanced.Therefore,the system χ is no longer a constant value and gradually

关 键 词：反铁磁 单轴应力 单晶 晶格畸变 

分 类 号：O469[理学—凝聚态物理]