1State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 2Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing 100871 3Ningxia Magvalley Novel Materials Technology Co., Ltd. New Energy Sub-Park, Ningdong Energy & Chemical Industry Base, Ningxia 751411
Abstract：To investigate the process of strain relaxation and resultant variation of microstructure and magnetic properties, low-doped La$_{0.825}$Sr$_{0.175}$MnO$_{3}$ epitaxial films with different thicknesses are deposited on LaAlO$_{3}$ substrates and strain induced nanopillars are discovered inside the La$_{0.825}$Sr$_{0.175}$MnO$_{3}$ film. Perpendicular oriented nanopillars mainly exist below 30 nm and tend to disappear above 30 nm. The distribution of nanopillars not only induce the variation of lattice parameters and local structural distortion but also lead to the deviation of easy magnetization axis from the perpendicular direction. Specifically, the out-of-plane lattice parameters of the film decrease quickly with the increase of the thickness but tend to be constant when the thickness is above 30 nm. Meanwhile, the variations of magnetic properties along in-plane and out-of-plane directions would also decline at first and they then remain nearly unchanged. Our work constructs the relationship between nanopillars and magnetic properties inside films. We are able to clearly reveal the effects of inhomogeneous strain relaxation.
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2019, Vol. 36 
