Spin gap in quasi-one-dimensional S=3/2 antiferromagnet CoTi2O5  

作　　者：徐浩航 刘庆元 辛潮 申沁鑫 罗军 周睿 程金光 刘健 陶玲玲 刘志国 霍明学 王先杰 隋郁 Hao-Hang Xu;Qing-Yuan Liu;Chao Xin;Qin-Xin Shen;Jun Luo;Rui Zhou;Jin-Guang Cheng;Jian Liu;Ling-Ling Tao;Zhi-Guo Liu;Ming-Xue Huo;Xian-Jie Wang;Yu Sui(School of Physics,Harbin Institute of Technology,Harbin 150001,China;School of Science,Changchun University of Science and Technology,Changchun 130022,China;Beijing National Laboratory for Condensed Matter Physics,and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;Laboratory for Space Environment and Physical Sciences,Harbin Institute of Technology,Harbin 150001,China;Southwest Institute of Applied Magnetics,Mianyang 621000,China)

机构地区：[1]School of Physics,Harbin Institute of Technology,Harbin 150001,China [2]School of Science,Changchun University of Science and Technology,Changchun 130022,China [3]Beijing National Laboratory for Condensed Matter Physics,and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [4]Laboratory for Space Environment and Physical Sciences,Harbin Institute of Technology,Harbin 150001,China [5]Southwest Institute of Applied Magnetics,Mianyang 621000,China

出　　处：《Chinese Physics B》2024年第3期609-617,共9页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 52372003);the Funds from Beijing National Laboratory for Condensed Matter Physics

摘　　要：Quasi-one-dimensional(1D)antiferromagnets are known to display intriguing phenomena especially when there is a spin gap in their spin-excitation spectra.Here we demonstrate that a spin gap exists in the quasi-1D Heisenberg antiferromagnet CoTi2O5 with highly ordered Co2+/Ti4+occupation,in which the Co2+ions with S=3/2 form a 1D spin chain along the a-axis.CoTi2O5 undergoes an antiferromagnetic transition at TN~24 K and exhibits obvious anisotropic magnetic susceptibility even in the paramagnetic region.Although a gapless magnetic ground state is usually expected in a quasi-1D Heisenberg antiferromagnet with half-integer spins,by analyzing the specific heat,the thermal conductivity,and the spin-lattice relaxation rate(1/T1)as a function of temperature,we found that a spin gap is opened in the spin-excitation spectrum of CoTi2O5 around TN,manifested by the rapid decrease of magnetic specific heat to zero,the double-peak characteristic in thermal conductivity,and the exponential decay of 1/T1 below TN.Both the magnetic measurements and the first-principles calculations results indicate that there is spin-orbit coupling in CoTi2O5,which induces the magnetic anisotropy in CoTi2O5,and then opens the spin gap at low temperature.

关 键 词：quasi-one-dimensional antiferromagnet magnetic anisotropy spin gap 

分 类 号：O469[理学—凝聚态物理]