Insights to unusual antiferromagnetic behavior and exchange coupling interactions in Mn_(23)C_(6)  

作　　者：Ze-Kun Yu Chao Zhou Kuo Bao Zhao-Qing Wang En-Xuan Li Jin-Ming Zhu Yuan Qin Yu-Han Meng Pin-Wen Zhu Qiang Tao Tian Cui 于泽坤;周超;包括;王兆卿;李恩萱;朱金铭;秦源;孟钰涵;朱品文;陶强;崔田

机构地区：[1]State Key Laboratory of Superhard Materials,College of Physics,Jilin University,Changchun 130012,China [2]Institute of High Pressure Physics,School of Physical Science and Technology,Ningbo University,Ningbo 315211,China

出　　处：《Chinese Physics B》2025年第3期152-159,共8页中国物理B(英文版)

摘　　要：We report the structural,mechanical and electromagnetic properties of the intermetallic compound Mn_(23)C_(6).The bulk Mn_(23)C_(6)sample was synthesized using high temperature high pressure quenching method(HTHPQM),and investigated in detail by x-ray diffraction,electron microscope,magnetization and electrical resistivity measurements,etc.First-principles calculation based on density functional theory ab intio simulation was carried out to calculate the bonding and electromagnetic properties of Mn_(23)C_(6).Based on our experimental and simulated results,the Mn_(23)C_(6)in this work is single phase of a faced-centered cubic structure with space group Fm-3m(No.225).Determined by SEM and TEM,the bulk sample consists of monocrystal Mn_(23)C_(6)crystals with 2-15μm grain sizes,it is the quick quenching method in the synthesizing process that brings such small crystal grain size.Archimedes method gives its density of 7.14 g/cm^(3),95.74%of its theoretically calculated density 7.458 g/cm^(3).Owing to the abundant Mn 3d electrons and a framework of strongly linked Mn atoms in Mn_(23)C_(6),the electrical conductivity is up to 8.47×10^(-4)Ω·m,which shows that Mn_(23)C_(6)is a good conductor.Our magnetic susceptibility analyses reveal a magnetization peak in the M-T curve at 104 K,combined with the M-H curve and Curie-Weiss law,this peak usually means the transformation between paramagnetic and antiferromagnetic orders.To gain an insight into the mechanism of the magnetic phase transition,we calculated the magnetic properties,and the results show that different from normal antiferromagnetic order,the magnetic orders in Mn_(23)C_(6)consist of three parts,the direct ferromagnetic and antiferromagnetic exchange coupling interactions between Mn atoms,and the indirect antiferromagnetic super-exchange interaction between Mn and C atoms.Therefore,we reveal that the Mn_(23)C_(6)is a complex magnetic competition system including different magnetic orders and interactions,instead of the normal long-range antiferromagnetic order

关 键 词：intermetallic compound(IMC) MAGNETISM high temperature high pressure(HTHP) density functional theory(DFT) 

分 类 号：TG1[金属学及工艺—金属学]