Exchange coupling and exchange bias in La0.7Sr0.3MnO3-SrRuO3 superlattices

Ultrathin Ferroelectric Films: Growth, Characterization, Physics and Applications

Ultrathin ferroelectric films are of increasing interests these years, owing to the need of device miniaturization and their wide spectrum of appealing properties. Recent advanced deposition methods and characterization techniques have largely broadened the scope of experimental researches of ultrathin ferroelectric films, pushing intensive property study and promising device applications. This review aims to cover state-of-the-art experimental works of ultrathin ferroelectric films, with a comprehensive survey of growth methods, characterization techniques, important phenomena and properties, as well as device applications. The strongest emphasis is on those aspects intimately related to the unique phenomena and physics of ultrathin ferroelectric films. Prospects and challenges of this field also have been highlighted.

Anomalous exchange bias at collinear/noncollinear spin interface

We report on the interfacial magnetic coupling in manganite bilayers of collinear ferromagnetic La_0.7Sr_0.3MnO₃ and noncollinear multiferroic TbMnO₃. Exchange bias is observed at the Néel temperature of TbMnO₃ (~41 K) due to the onset of long-range antiferromagnetic ordering in the Mn spin sublattice. Interestingly, an anomalous plateau of exchange bias emerges at the ordering temperature of Tb spins (~10 K), and we ascribe this unique feature to the strong coupling between Tb and Mn spin sublattices in TbMnO₃, which in turn influences the magnetic coupling across the interface. On the other hand, the enhancement of coercivity in La_0.7Sr_0.3MnO₃/TbMnO₃ shows monotonous temperature dependence. Our results illustrate a strong interfacial magnetic interaction at the La_0.7Sr_0.3MnO₃/TbMnO₃ interface, highlighting the roles of competing spin orders, magnetic frustration, and coupling between multiple spin sublattices in artificial collinear/noncollinear spin heterostructures.