Magneto-optical and magnetic force microscopy of Al-deficient LaAlO3/SrTiO3 interfaces

The nature of magnetism at the LaAlO3/SrTiO3 (LAO/STO) interface is not well understood. Magnetic force microscopy (MFM) imaging has revealed electronically tunable domains at the LAO/STO interface near the insulating transition point[1]. Recent reports indicate that room temperature magnetic ordering can be achieved in LAO/STO heterostructure by controlling the Al deficiency of the LAO upper layer during growth [2]. By taking advantage of optically-induced magnetism in STO[3], scanning magneto-optical Kerr effect (MOKE) microscopy can be used in addition to MFM to map magnetic domains spatially. Ultrafast MOKE can then be used to study magnetic domain dynamics and transitions with picosecond resolution using optical pump and probe measurements. Observing apparent ferromagnetism at this interface will offer new insights into the nature of magnetism and the source of this phenomenon.

 

[1] F. Bi, et al. Nat Commun 5, 5019 (2014).

[2]D.S. Park, et al., Nat Commun 11 3650 (2020) 

[3] W. Rice, Ambwani, P., Bombeck, M. et al. Nature Mater 13, 481–487 (2014).