Interfacial Coupling-Induced Ferromagnetic Insulator Phase in Manganite Film

详细信息    查看全文

• 作者：Bangmin Zhang ; Lijun Wu ; Wei-Guo Yin ; Cheng-Jun Sun ; Ping Yang ; T. Venkatesan ; Jingsheng Chen ; Yimei Zhu ; Gan Moog Chow
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：July 13, 2016
• 年：2016
• 卷：16
• 期：7
• 页码：4174-4180
• 全文大小：518K
• 年卷期：0
• ISSN：1530-6992

文摘

Interfaces with subtle differences in atomic and electronic structures in perovskite ABO₃ heterostructures often yield intriguingly different properties, yet their exact roles remain elusive. Here, we report an integrated study of unusual transport, magnetic, and structural properties of Pr_0.67Sr_0.33MnO₃ film on SrTiO₃ substrate. The variations in the out-of-plane lattice constant and BO₆ octahedral rotation across the Pr_0.67Sr_0.33MnO₃/SrTiO₃ interface strongly depend on the thickness of the Pr_0.67Sr_0.33MnO₃ film. In the 12 nm film, a new interface-sensitive ferromagnetic polaronic insulator (FI′) phase is formed during the cubic-to-tetragonal phase transition of SrTiO₃, apparently due to the enhanced electron–phonon interaction and atomic disorder in the film. The transport properties of the FI′ phase in the 30 nm film are masked because of the reduced interfacial coupling and smaller interface-to-volume ratio. This work demonstrates how thickness-dependent interfacial coupling leads to the formation of a theoretically predicted ferromagnetic–polaronic insulator, as illustrated in a new phase diagram, that is otherwise ferromagnetic metal (FM) in bulk form.