Charge transfer-induced magnetic exchange bias and electron localization in (111)- and (001)-oriented LaNiO3/LaMnO3 superlattices
Charge transfer-induced magnetic exchange bias and electron localization in (111)- and (001)-oriented LaNiO3/LaMnO3 superlattices
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DOI：
10.1063/1.4978358
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发表时间：
2017-03
影响因子：
4
通讯作者：
Haoming Wei;J. Barzola-Quiquia;Chang Yang;C. Patzig;T. Höche;P. Esquinazi;M. Grundmann;M. Lorenz-M.-Lo
中科院分区：
文献类型：
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作者：
Haoming Wei;J. Barzola-Quiquia;Chang Yang;C. Patzig;T. Höche;P. Esquinazi;M. Grundmann;M. Lorenz-M.-Lo
采用脉冲激光沉积法在（111）和（001）晶向SrTiO 3衬底上生长了具有单层台阶结构的高质量晶格匹配LaNiO 3/LaMnO 3超晶格。与先前报道的实验相反，磁交换偏置被观察到，可重复地发生在（111）-和（001）-取向的超晶格中，分别具有5和7个单位晶胞的薄单层。从理论上解释了交换偏置是由Ni原子上的电荷转移引起的磁矩引起的。低温下的磁化强度数据表明超晶格中存在两个磁相，Neel温度约为10 K。电输运测量揭示了一个金属-绝缘体过渡与强本地化的电子在超晶格与薄的LaNiO 3层的4个单位电池，其中的电输运是由二维可变范围跳跃为主。
High-quality lattice-matched LaNiO3/LaMnO3 superlattices with monolayer terrace structure have been grown on both (111)- and (001)-oriented SrTiO3 substrates by pulsed laser deposition. In contrast to the previously reported experiments, a magnetic exchange bias is observed that reproducibly occurs in both (111)- and (001)-oriented superlattices with the thin single layers of 5 and 7 unit cells, respectively. The exchange bias is theoretically explained by charge transfer-induced magnetic moments at Ni atoms. Furthermore, magnetization data at low temperature suggest two magnetic phases in the superlattices, with Neel temperature around 10 K. Electrical transport measurements reveal a metal-insulator transition with strong localization of electrons in the superlattices with the thin LaNiO3 layers of 4 unit cells, in which the electrical transport is dominated by two-dimensional variable range hopping.