对La_（2-x）Sr_xCuO_4（LSCO）薄膜（0.10 < x < 0.25）的电导各向异性和磁电阻进行了详细的研究。这两个观测值是有希望的条纹检测。通过测量零磁场下的横向电阻Rxy，揭示了电导各向异性的细微特征。它表明，Rxy的符号取决于LSCO霍尔条相对于衬底的平台结构的取向。因此，单元格高的衬底台阶边缘必须是薄膜生长过程中反相边界的主要成核源。结果表明，在105 K时，Rxy的测量灵敏度足以检测SrTiO 3（100）（STO）衬底的ε-四元相变。LSCO薄膜的MR在0.10 < x < 0.25时表现出非单调的温度依赖性，这是由于MR在90 K以上出现线性项所致。我们表明，线性MR尺度与霍尔电阻率的绝对值，与温度无关的比例常数。这样的缩放表明，线性MR起源于由结构或电子不均匀性引起的电流畸变。条纹的MR和电导各向异性的可能作用进行了讨论。
英文摘要：
We have performed a detailed study of conductance anisotropy and magnetoresistance (MR) of La2-xSrxCuO4 (LSCO) thin films (0.10 < x < 0.25). These two observables are promising for the detection of stripes. Subtle features of the conductance anisotropy are revealed by measuring the transverse resistance Rxy in zero magnetic field. It is demonstrated that the sign of Rxy depends on the orientation of the LSCO Hall bar with respect to the terrace structure of the substrate. Unit-cell-high substrate step edges must therefore be a dominant nucleation source for antiphase boundaries during film growth. We show that the measurement of Rxy is sensitive enough to detect the cubic-tetragonal phase transition of the SrTiO3(100) (STO) substrate at 105 K. The MR of LSCO thin films shows for 0.10 < x < 0.25 a non-monotonic temperature dependence, resulting from the onset of a linear term in the MR above 90 K. We show that the linear MR scales with the absolute Hall resistivity, with the constant of proportionality independent of temperature. Such scaling suggests that the linear MR originates from current distortions induced by structural or electronic inhomogeneities. The possible role of stripes for both the MR and the conductance anisotropy is discussed throughout the paper.
Single-ion anisotropy, Dzyaloshinskii-Moriya interaction and negative magnetoresistance of the spin-1/2 pyrochlores R2V2O7
采用密度泛函方法研究了自旋为1/2的高温超导体R2 V2 O 7的电子和磁性.与通常的看法相反，自旋为1/2的V4+离子被发现具有显著的易轴单离子各向异性。的|D/J|从Lu 2 V2 O 7的磁振子量子霍尔效应推导出的比率，其中J是最近邻自旋交换，D是Dzyaloshinskiii-Moriya参数，远大于从我们的计算估计的值（即，0.32与0.05）。我们发现，这种差异是由于忽略的V4+离子的单离子各向异性，和观察到的负磁阻R2 V2 O 7产生一个新的机制。
Temperature- and Bias-dependence of magnetoresistance in doped manganite thin film trilayer junctions
La $%_{0.67}$ Sr $_{0.33}$ MnO的薄膜三层结$_3$ - SrTiO $_3$ - La $_{0.67}$ Sr $_{0.33}$ MnO $_3$在14 K下在100 Oe左右的磁场中显示出9.7倍的电阻变化。结的磁电阻是偏置和温度相关的。与偏压和温度依赖性相关的能量尺度是一个数量级。同一组能量也决定了结的微分电导的偏置和温度依赖性。我们讨论了这些结果在结势垒界面的金属簇夹杂物。
