Novel Transitions in Doped Mott—Insulator KxCoO2

作     者：YANGHai-Peng LUXi-Feng WENHai-Hu 

作者机构：NationalLaboratoryforSuperconductivityInstituteofPhysicsandCenterforCondensedMatterPhysicsChineseAcademyofSciencesBeijing100080 

出 版 物：《Chinese Physics Letters》 (中国物理快报（英文版）)

年 卷 期：2003年第20卷第5期

页      面：729-730页

核心收录：

学科分类：081704[工学-应用化学] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 070205[理学-凝聚态物理] 08[工学] 0817[工学-化学工程与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 070301[理学-无机化学] 0702[理学-物理学] 

基　　金：国家自然科学基金 国家科技部项目 

主　　题：磁化系数 钾掺杂 氧化钴 温度测量 铁磁性 超顺磁性 

摘      要：By measuring the temperature dependence of the magnetic susceptibility, two distinct transitions have been observed in potassium doped cobalt oxide KxCoO2 (x = 0.2-1.0). The transition around 125K corresponds to a phase transition between a weak ferromagnetic plus a strong superparamagnetic phase (below 125K) and a superparamagnetic phase (above 125K). The susceptibility above the Curie point Tc cannot be described by the Curie-Weise law, being consistent with the superparamagnetism. Magnetization-hysteresis-loops have been measured in different temperature regions to uncover the underlying physics. The second transition near 30.8K shows a strong novelty.