Chiral magnetism, skyrmions and nanoscale superparamagnetism in oxide interfaces

The electronic properties of the interface between insulating oxides is a subject of great current interest. These oxide heterostructures exhibit a range of novel phenomena that do not occur in the parent bulk compounds. One of the prominent examples is the appearance of magnetism at the interface between the band insulators LaAlO3 (LAO) and SrTiO3 (STO). In the first part of my talk, I will discuss the possibility of realizing chiral magnetism and novel magnetic states, namely spirals and topological spin textures such as skyrmions, in oxide interfaces [1,2,3]. In the second part of my talk, I will report a new emergent phenomenon at another interface, LaMnO3/SrTiO3 (LMO/STO), in which an antiferromagnetic insulator abruptly transforms as a function of LMO thickness into a magnetic state exhibiting unusual nanoscale superparamagnetic.dynamics [4]. I will discuss a theoretical model to understand this phenomenon.

[1] S. Banerjee, O. Erten and M. Randeria, Nature Physics 9, 626 (2013).
[2] S. Banerjee, J. Rowland, O. Erten and M. Randeria, Phys. Rev. X 4, 031045 (2014).
[3] J. Rowland, S. Banerjee and M. Randeria, arXiv:1509.07508 (2015).
[4] Y. Anahory et al., arXiv:1509.01895 (2015).