Manganite/Cuprate Superlattice as Artificial Reentrant Spin Glass. Issue 14 (4th May 2016)

• Record Type: Journal Article
• Authors: Ding, Junfeng; Cossu, Fabrizio; Lebedev, Oleg I.; Zhang, Yuqin; Zhang, Zhidong; Schwingenschlögl, Udo; Wu, Tom
• Is Part Of: Advanced materials interfaces. Volume 3:Issue 14(2016)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2016-05-04
• Subjects: cuprate -- first‐principles calculations -- interfaces -- manganite -- reentrant spin glass; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201500676
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract : Emerging physical phenomena at the unit‐cell‐controlled interfaces of transition‐metal oxides have attracted lots of interest because of the rich physics and application opportunities. This work reports a reentrant spin glass behavior with strong magnetic memory effect discovered in oxide heterostructures composed of ultrathin manganite La0.7 Sr0.3 MnO3 (LSMO) and cuprate La2 CuO4 (LCO) layers. These heterostructures are featured with enhanced ferromagnetism before entering the spin glass state: a Curie temperature of 246 K is observed in the superlattice with six‐unit‐cell LSMO layers, while the reference LSMO film with the same thickness shows much weaker magnetism. Furthermore, an insulator–metal transition emerges at the Curie temperature, and below the freezing temperature the superlattices can be considered as a glassy ferromagnetic insulator. These experimental results are closely related to the interfacial spin reconstruction revealed by the first‐principles calculations, and the dependence of the reentrant spin glass behavior on the LSMO layer thickness is in line with the general phase diagram of a spin system derived from the infinite‐range SK model. The results of this work underscore the manganite/cuprate superlattices as a versatile platform of creating artificial materials with tailored interfacial spin coupling and physical properties. Abstract : Reentrant spin glass state with enhanced ferromagnetism is observed in ultrathin manganite/cuprate superlattices made of ferromagnetic La0.7 Sr0.3 MnO3 and antiferromagnetic La2 CuO4 . The evolution of the rich magnetic properties is attributed to the competition between multiple energetic ground states at the interfaces, which is confirmed by first‐principles calculations.