Systematic study of short-range antiferromagnetic order and the spin-glass state in lightly doped La 2-x Sr x CuO 4
Systematic study of short-range antiferromagnetic order and the spin-glass state in lightly doped La 2-x Sr x CuO 4
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轻掺杂La 2-x Sr x CuO 4 中短程反铁磁序和自旋玻璃态的系统研究
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
K. Yamada
中科院分区：
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作者：
S. Wakimoto;S. Ueki;Y. Endoh;K. Yamada
对轻掺杂La_（2-x）Sr_xCuO_4（x=0.03，0.04和0.05）单晶进行了系统的磁化率测量。对于所有样品的面内磁化率的温度依赖性显示出典型的自旋玻璃化特征，其中自旋玻璃化转变温度Tg分别为6.3K、5.5K和5.0K（x=0.03、0.04和0.05）。从所有样品的面内磁化率中提取的典型自旋玻璃序参数遵循通用标度曲线。另一方面，面外磁化率在高于Tg的温度Tdv以下偏离居里定律。与Wakimoto等人以前的仪器能量分辨率为0.25 meV的中子散射结果相比，Tdv的x依赖性定性地与Tel的x依赖性相同，Tel是弹性磁散射在（π，π）附近发展的温度。因此，在轻掺杂区的La 2-xSrxCuO 4的修订的磁相图提出。从面内磁化率计算的居里常数是独立的Sr浓度。基于团簇自旋玻璃模型，这一事实可能反映了掺杂空穴在CuO 2平面上的不均匀分布，例如在条纹结构中。
Systematic measurements of the magnetic susceptibility were performed on single crystals of lightly doped La2-xSrxCuO4 (x=0.03, 0.04 and 0.05). For all samples the temperature dependence of the in-plane magnetic susceptibility shows typical spin-glass features with spin-glass transition temperatures Tg of 6.3K, 5.5K and 5.0K for x=0.03, 0.04 and 0.05, respectively. The canonical spin-glass order parameter extracted from the in-plane susceptibility of all the samples follows a universal scaling curve. On the other hand, the out-of-plane magnetic susceptibility deviates from Curie law below a temperature Tdv, higher than Tg. Comparing with previous neutron scattering results with an instrumental energy resolution of 0.25 meV from Wakimoto et al., the x-dependence of Tdv is qualitatively the same as that of Tel, the temperature below which the elastic magnetic scattering develops around (pi, pi). Thus, a revised magnetic phase diagram in the lightly doped region of La2-xSrxCuO4 is proposed. The Curie constants calculated from the in-plane susceptibility are independent of the Sr concentration. On the basis of the cluster spin-glass model, this fact might reflect an inhomogeneous distribution of doped holes in the CuO2 plane, such as in a stripe structure.