La$_{0.7}$Ce$_{0.3}$MnO$_3$ thin films of different thicknesses, degrees of CeO$_2$-phase segregation and oxygen deficiency, grown on SrTiO$_3$ single crystal substrates, were comparatively investigated with respect to both their spectral and temperature-dependent photoconductivity (PC) and their magnetoresistance (MR) behaviour under photoexcitation. While as-grown films were insensitive to optical excitation, oxygen reduction appeared to be an effective way to decrease the film resistance, but the film thickness was found to play a minor role. However, from the evaluation of the spectral behaviour of the PC and the comparison of the MR of the LCeMO/substrate-samples with a bare substrate under illumination we find that the photoconductivity data reflects not only contributions from (i) photogenerated charge carriers in the film and (ii) carriers injected from the photoconductive substrate (as concluded from earlier works), but also (iii) a decisive parallel photoconduction in the SrTiO$_3$ substrate. Furthermore -- also by analyzing the MR characteristics -- the unexpected occurence of a strong electroresistive effect in the sample with the highest degree of CeO$_2$ segregation and oxygen deficiency could be attributed to the electroresistance of the SrTiO$_3$ substrate as well. The results suggest a critical reconsideration and possibly a reinterpretation of several previous photoconductivity and electroresistance investigations of manganite thin films on SrTiO$_3$.
Colossal enhancement of magnetoresistance in La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ / Pr$_{0.67}$Ca$_{0.33}$MnO$_{3}$ multilayers: reproducing the phase-separation scenario
Colossal magnetoresistance without phase separation: Disorder-induced spin glass state and nanometer scale orbital-charge correlation in half doped manganites
本文研究了高质量$A$位无序（固溶体）$_{0.5}$单晶在自旋玻璃绝缘体与磁阻铁磁金属相界附近的磁学和电学性质。详细分析了Eu $_{0.5}$ Ba $_{0.5}$ MnO $_3$的交流磁化率和X射线漫散射随温度的变化关系。具有小带宽的Ln $_{0.5}$ Ba $_{0.5}$ MnO $_3$晶体中随机势扰动的均匀性产生了均匀的短程电荷/轨道有序，而不是相分离，从而产生了近原子的自旋玻璃态。值得注意的是，这种微观无序的“CE玻璃”状态本身就能够产生巨大的磁阻。
Magnetoresistance studies of $La_{2/3} Sr_{1/3} MnO_3$ - $YBa_2 Cu_3 O_7$ - $La_{2/3} Sr_{1/3} Mn O_3$ trilayers with ferromagnetic coupling along the nodal direction of $YBa_2 Cu_3 O_7$
Magnetization depinning transition, anisotropic magnetoresistance and inplane anisotropy in two polytypes of La$_{2 / 3}$Sr$_{1 / 3}$MnO$_{3}$ epitaxial films
在10 ~ 300 K的温度范围内，测量了La $_{2 / 3}$ Sr $_{1 / 3}$ MnO的[001]和[110]外延膜的等温磁电阻[R（$θ$）]。这些多型体的易磁化轴与Mn-O- Mn键相对于衬底平面上的晶轴的取向以及其中一些轴的能量等效性密切相关。在低场下，[001]和[110]型薄膜的磁化矢量（$\vec{M}$）分别沿[110]和[001]方向钉扎。一个磁化取向相变（MRPT），表现为一个不连续性和滞后$R(ψ)$其中$ψ$是之间的角度$\vec{H}$和易轴的$\vec{H}$低于一个临界值$\vec{H}^*$已建立。在H-T平面上建立了钉扎相和脱钉相的边界。在[110]薄膜中看到的高度稳定的磁化钉扎与其独特定义的易磁化轴有关。两种多型体的$\vec{I} \bot \vec{H}$和$\vec{I} \| \vec{H}$的等温电阻R $_\bot$和R $_\|$分别在所有场（$0 \leq H \leq 3500Oe$）和温度范围（10 K-300 K）下遵循不等式R $_\bot >$ R $_\|$。一个完整的旋转磁阻的分析进行了Döring理论的框架内的单晶样品中的MR。从预测的角度依赖性的强烈偏差被认为是在磁化的不可逆制度。
Collapse of Jahn-Teller Phonons in La$_{1-x}$Sr$_{x}$MnO$_3$ with Weak Magnetoresistance
University of Colorado Boulder（科罗拉多大学博尔德分校）；Oak Ridge National Laboratory（橡树岭国家实验室）；Japan Atomic Energy Agency（日本原子能机构）；High Energy Accelerator Research Organization (KEK)（高能加速器研究机构）；Comprehensive Research Organization for Science and Society（综合科学研究组织）；Karlsruhe Institute of Technology（卡尔斯鲁厄理工学院）
Effect of "dipolar-biasing" on the tunability of tunneling magnetoresistance in transition metal oxide systems
我们在La $_{2/3}$ Sr $_{1/3}$ MnO $_{3}$与CoFe $_{2}$ O $_{4}$的复合物中观察到一种不寻常的隧穿磁电阻（TMR）现象，其中TMR随外加磁场的变化曲线表明了一种“负矫顽场”。追溯其起源到一个“偶极偏置”的La $_{2/3}$ Sr $_{1/3}$ MnO $_{3}$由CoFe $_{2}$ O $_{4}$，我们表明，即使是一个单一的复合材料的TMR可以连续调谐，使电阻峰值或最高灵敏度的TMR可以定位在任何地方的磁场轴与适当的磁历史的样品。TMR的这种前所未有的可调谐性的现象通常应该存在于所有这样的复合材料中。
Asymmetric magnetoresistance in 3$d$-5$d$ based La$_{0.67}$Ca$_{0.33}$MnO$_3$/SrIrO$_3$ bilayer: The role of unidirectional anisotropy
Jawaharlal Nehru University（贾瓦哈拉尔·尼赫鲁大学）；Indian Institute of Technology, Hauz Khaz（印度理工学院豪兹卡兹校区）；Special Centre for Nanoscience, Jawaharlal Nehru University（贾瓦哈拉尔·尼赫鲁大学纳米科学特别中心）；UGC-DAE Consortium for Scientific Research, Indore（印度古物与考古学联合会-原子能部科学研究中心）
Temperature evolution of magnetic phases near the thickness-dependent metal-insulator transition in La$_{1-x}$Sr$_x$MnO$_3$ thin films observed by XMCD
钙钛矿型锰氧化物由于具有庞磁电阻（CMR）和半金属性等优良的物理性质，被认为是自旋电子学的候选材料。然而，当厚度减小到几个单层（ML）时，它们的铁磁（FM）性质在薄膜中经常被抑制。为了研究磁性相如何在顺磁（PM）到FM相变边界附近演化，我们对La $_{1-x}$ Sr $_{x}$ MnO $_3$（LSMO，$x=0.4$）薄膜进行了随温度变化的X射线磁性圆二色性（XMCD）实验，该薄膜的厚度（8 ML）接近FM金属相和PM绝缘相之间的边界。通过利用XMCD的元素选择性，我们已经定量地估计了PM和超顺磁（SPM）相以及FM相作为温度的函数的分数。结果可以合理地描述基于微观相分离模型。
Simultaneous MOKE imaging and measurement of magneto-resistance with vector magnet: a low noise customized setup for low field magnetic devices and thin films characterization
Dirac semimetal strontium iridate thin films with strong spin-orbit interaction for magnetic heterostructures
Kotelnikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences（俄罗斯科学院科捷利尼科夫无线电工程与电子研究所）；National Research University "Higher School of Economics", Faculty of Physics（国立研究大学高等经济大学物理系）；Moscow Institute of Physics and Technology (National Research University)（莫斯科物理技术学院（国立研究大学））
