缺氧条件下准一维自旋梯状结构化合物(Sr1-xCax)14Cu24O41-δ的磁化率特性研究  

Study on the magnetic susceptibility of quasi-one-dimensional spin ladder compounds (Sr_(1-x)Ca_x)_(14)Cu_(24)O_(41-δ) with oxygen deficiency

作　　者：汪丽莉[1] 熊锐[1] 魏伟[1] 胡妮[1] 林颖[1] 朱本鹏[1] 汤五丰[1] 余祖兴[1] 汤征[1] 石兢[1] 

机构地区：[1]武汉大学物理系声光材料与器件教育部重点实验室,武汉430072

出　　处：《物理学报》2008年第7期4334-4340,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10474074,10534030,10674105)资助的课题~~

摘　　要：在空气环境中采用固相反应方法制备出三种A位Ca掺杂自旋梯状结构化合物(Sr1-xCax)14Cu24O41-δ样品(x=0,0.25,0.43)能量损失谱(EDS)分析表明,该体系Ca掺杂样品均严重缺氧(分别对应的缺氧含量δ=7.64,6.99,6.67).X射线衍射(XRD)结果显示,所有样品均为单相,并且晶格常数a,b,c的值随着缺氧含量δ的增加而增大.1T直流磁场下的磁化率-温度曲线及其拟合结果表明,对无Ca掺杂样品Sr14Cu24O41-δ(δ=7.64),氧含量减少导致自旋链上空穴数的减少,自旋链上自由自旋的Cu离子数目增大,而参与二聚化的Cu离子数目略有减小;而对Ca掺杂样品(Sr1-xCax)14Cu24O41-δ,随着Ca含量的增加,样品中氧缺失量降低,但Ca掺杂引起空穴减少的程度更强.Three samples of spin ladder compounds （Sr1-xCax）14Cu24O41-δ（ N = 0, 0.25, 0.43 ） were prepared by conventional solid-state reaction in air. The EDS results revealed that all three samples are in the state of oxygen deficiency （ δ= 7.64,6.99 and6.67, respectively） . X-ray diffraction showed that the samples have single phase, and the lattice parameters a, b, c decrease continuously with the increase of oxygen content. For the sample withoutca Ca doping, the measurement of magnetic susceptibility showed that oxygen deficiency reduces the number of holes and Z-R singlets, and leads to the increase of free spins and the decrease of dimer spins. For Ca doped samples, the oxygen deficiency decreases with the increase of Ca content, but Ca doping enhances the transfer of holes from spin chains to spin ladders.

关 键 词：自旋梯状结构化合物 氧缺位 晶体结构 磁化率 

分 类 号：O482.5[理学—固体物理]