Thickness-dependent ferromagnetic metal to paramagnetic insulator transition in LaSrMnO thin films studied by X-ray magnetic circular dichroism

芝田 悟朗*; 吉松 公平*; 坂井 延寿*; Singh, V. R.*; Verma, V.*; 石上 啓介*; 原野 貴幸*; 門野 利治*; 竹田 幸治; 岡根 哲夫; et al.

Physical Review B, 89(23), p.235123_1 - 235123_5, 2014/06

AA2015-0419.pdf:0.33MB

https://doi.org/10.1103/PhysRevB.89.235123

Metallic transition-metal oxides undergo a metal-to-insulator transition (MIT) as the film thickness decreases across a critical thickness of several monolayers (MLs), but its driving mechanism remains controversial. We have studied the thickness-dependent MIT of the ferromagnetic metal LaSrMnO by X-ray absorption spectroscopy and X-ray magnetic circular dichroism. The results suggest that the ferromagnetic phase gradually and most likely inhomogeneously turns into the paramagnetic phase and both phases abruptly become insulating at the critical thickness.