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arXiv 0909.2842cond-mat.str-elcond-mat.dis-nn
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轻掺杂La_{2} CuO_{4}莫特绝缘体的大正磁阻效应

Large Positive Magnetoresistance of the Lightly Doped La_{2}CuO_{4} Mott Insulator

I. Raicevic, Dragana Popovic, C. Panagopoulos, T. Sasagawa

摘要:

本文测量了轻掺Sr(La_{2-x} Sr_xCuO_4)或Li(La_2 Cu_{1-x} Li_xO_4)(x=0.03)的La_2CuO_4单晶在平行和垂直于CuO_2面的磁场下的面内和面外磁电阻(MR)。La_{1.97} Sr_{0.03} CuO_4和La_2 Cu_{0.97} Li_{0.03} O_4在远低于自旋玻璃转变温度(SG)T_{sg}的温度(T)下都表现出正MR的出现,此时电荷动力学也是玻璃态的。该正MR随着T->0而增长,并且显示滞后和记忆。在这种情况下,面内电阻R_{ab}(T,B)由标度函数描述,表明在低T下,处于相同无序局域态的两个空穴之间的短程库仑排斥起着关键作用。结果突出了这种磁性材料与广泛的一类研究充分的无序绝缘体之间的相似性。

英文摘要:

The in-plane and out-of-plane magnetoresistance (MR) of single crystals of La_2CuO_4, lightly doped (x=0.03) with either Sr (La_{2-x}Sr_xCuO_4) or Li (La_2Cu_{1-x}Li_xO_4), have been measured in the fields applied parallel and perpendicular to the CuO_2 planes. Both La_{1.97}Sr_{0.03}CuO_4 and La_2Cu_{0.97}Li_{0.03}O_4 exhibit the emergence of a positive MR at temperatures (T) well below the spin glass (SG) transition temperature T_{sg}, where charge dynamics is also glassy. This positive MR grows as T->0 and shows hysteresis and memory. In this regime, the in-plane resistance R_{ab}(T,B) is described by a scaling function, suggesting that short-range Coulomb repulsion between two holes in the same disorder-localized state plays a key role at low T. The results highlight similarities between this magnetic material and a broad class of well-studied, nonmagnetic disordered insulators.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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