Lorentz transmission electron microscopy observation of magnetic domains in LaSr(Mn,Al)O

Mori, Shigeo*; Yoshidome, Kazuhiro*; Nagamine, Yuki*; Togawa, Yoshihiko*; Yoshii, Kenji  ; Takenaka, Koshi*

Nonmagnetic Al substitution effect on the stability of a ferromagnetic (FM) metallic state indouble-exchange manganite, LaSrMnO, was investigated by Lorentz transmission electronmicroscopy (TEM), in combination with magnetic measurements. Both FM transition temperature(Tc) and the rhombohedral-to-orthorhombic (R-to-O) transition temperature (Ts) decreased by a few percent of Al substitution. An in situ Lorentz TEM observation revealed that drastic change of the FM domain structure took place through the R-to-O structural transition. The magnetization decreased slightly at Ts and characteristic spin-glass state is realized in the low-temperature region below Ts.