La1−xSrxCuO2.5as a Doped Spin-Ladder Compound
La1−xSrxCuO2.5as a Doped Spin-Ladder Compound
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La1−xSrxCuO2.5 作为掺杂自旋梯化合物
DOI：
10.1006/jssc.1996.0172
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发表时间：
1996
影响因子：
5.4
通讯作者：
Z. Hiroi
中科院分区：
文献类型：
--
作者：
Z. Hiroi
本文报道了La{sub 1-x}Sr{sub x}CuO{sub 2.5} （0 {le} x {le} 0.20）的高压合成、结构表征和物理性质。在6gpa高压下制备的未掺杂LaCuO{sub 2.5}结晶为CaMnO{sub 2.5}结构，是缺阴离子钙钛矿的原型之一。粉末x射线衍射图的Rietveld分析明显显示出由Cu-O阶梯组成的准一维结构。磁化率测量结果表明，S = 1/2 Heisenberg反铁磁阶梯体系的自旋液体基态具有490 K的大能隙，与理论预期一致。用Sr代替La实现了系统的空穴掺杂。在掺杂的电阻率测量中观察到一个戏剧性的绝缘体到金属的转变，但是，对于轻掺杂的自旋阶梯系统，没有理论预测的超导迹象。
The high-pressure synthesis, structural characterization, and physical properties of La{sub 1-x}Sr{sub x}CuO{sub 2.5} (0 {le} x {le} 0.20) are reported. The nondoped LaCuO{sub 2.5} prepared at high pressure of 6 GPa crystallizes in the CaMnO{sub 2.5} structure which is one of the prototypes of anion-deficient perovskites. The Rietveld analysis of the powder X-ray diffraction pattern remarkably shows a quasi-one-dimensional structure composed of Cu-O ladders. The magnetic susceptibility measurements suggest a spin liquid ground state with a large energy gap of 490 K as theoretically expected for a S = 1/2 Heisenberg antiferromagnetic ladder system. Systematic hole-doping is achieved by substituting Sr for La. A dramatic insulator-to-metal transition has been observed in the resistivity measurements on doping, but, with no signs of superconductivity as predicted theoretically for a lightly doped spin-ladder system.