立方C15b型YbCu_(5-x)In_x(0≤x≤1)中的原子混合价态与价态转移  

THE MIXED-VALENCE STATE AND FIRST-ORDER VALENCE TRANSITION BEHAVIOR OF CUBIC C15b-TYPE YbCu_(5-x)In_x(0≤x≤1) SYSTEM

作　　者：鲁彦涛[1] 陈亮[1] 夏炜炜[1] 梅烨[1] 曹永珍[1] 何军辉[1] 

机构地区：[1]扬州大学物理科学与技术学院,江苏扬州225002

出　　处：《低温物理学报》2009年第4期323-327,共5页Low Temperature Physical Letters

摘　　要：利用电弧熔炼方法制备了YbCu5-xInx(x=0.2,0.4,0.6,0.8,1)稀土金属相间化合物样品.多晶X射线衍射分析表明样品具有立方C15b型结构,并发现其晶胞参数随In含量的增加而线性增加.利用SQUID技术测量了样品在4.2K和300K之间的磁化强度与温度变化曲线,结果表明YbCu4In在40K附近显示出明显的具有一级相变特征的Yb离子价态转移现象;在150K以上YbCu5-xInx样品显示居里-外斯型(Curie-Weiss)型顺磁行为,Yb离子为局域三价态(Yb3+,4f13,J=7/2,μeff=4.54μB),这和先前报道的文献一致.Rare-earth intermetallics ternary C15b-type YbCu5-xInx samples were prepared by arc-melting method. Polycrystalline XRD shows that the samples have a cubic C15b-type structure, and we also found that the lattice constant of YbCu5-x Inx compounds increases linearly with In-content increasing. The M-T curves, which measured by SQUID technique, reveals that the first-order valence transition in YbCu5-x Inx shifts to higher temperature and becomes broadened significantly with decreasing In-content and above 150K the samples display Curie-Weiss para- magnetic behavior, the Yb ion was localized trivalent state（Yb3＋,4f^13,J=7/2,μeff=4.5μB）.

关 键 词：C15b型结构 价态转移 KONDO效应 磁化率 

分 类 号：O469[理学—凝聚态物理]