Department of Physics , Indian Institute of Technology Madras , Chennai 600036 , Tamil Nadu , India.
Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN , 6 Bd du Marechal Juin , F-14050 Caen Cedex, France.
ACS Appl Mater Interfaces. 2018 Dec 19;10(50):44190-44196. doi: 10.1021/acsami.8b17385. Epub 2018 Dec 7.
A strong perpendicular magnetocrystalline anisotropy (PMA) in antiferromagnetically coupled SrRuO(17 uc (unit cell))/PrMnO( n uc) superlattices effectively reconstructs the interfacial spin ordering. The occurrence of significant anisotropic interfacial antiferromagnetic coupling between the Ru and Mn ions is systematically tuned by varying the PrMnO layer thickness in ultrathin scale from 3 to 12 uc, which is associated with a rise in PMA energy from 0.28 × 10 to 1.60 × 10 erg/cm. The analysis using the Stoner-Wohlfarth model and density functional theory confirm that the exchange anisotropy is the major contribution to the PMA. The superlattices with PrMnO layer thickness ≥7 uc exhibit the tunneling-like transport of Ru 4d electrons, which is rather expected in the stronger antiferromagnetically coupled superlattices with thinner PrMnO layer. Tunneling-like transport at thicker spacer layer in the SrRuO-PrMnO superlattice system is an unique feature of two ferromagnet-based superlattices. Our investigations show that the technologically important interfacial magnetic coupling, PMA, and tunneling magnetoresistance could be achieved in a periodically stacked bilayer and can be precisely manipulated by the size effect in ultrathin scale.
反铁磁耦合 SrRuO(17 uc( 单位晶胞))/PrMnO( n uc) 超晶格中强烈的垂直磁各向异性 (PMA) 有效地重构了界面自旋有序。通过在超晶格厚度从 3uc 到 12uc 的超薄范围内改变 PrMnO 层厚度，系统地调节 Ru 和 Mn 离子之间的各向异性界面反铁磁耦合，其与 PMA 能量从 0.28×10 到 1.60×10 erg/cm 的增加有关。利用 Stoner-Wohlfarth 模型和密度泛函理论的分析证实，交换各向异性能是 PMA 的主要贡献者。在 PrMnO 层厚度≥7uc 的超晶格中表现出 Ru 4d 电子的隧道样输运，这在具有更薄 PrMnO 层的较强反铁磁耦合超晶格中是预期的。在 SrRuO-PrMnO 超晶格体系中，较厚的间隔层中的隧道样输运是两个基于铁磁体的超晶格的独特特征。我们的研究表明，在周期性堆叠的双层中可以实现技术上重要的界面磁耦合、PMA 和隧道磁电阻，并且可以通过超薄范围内的尺寸效应精确地调节它们。
