Phase Separation in La_<1-x>Sr_xMnO_<3+δ> Nanocrystals Studied by Electron Spin Resonance(Condensed matter: electronic structure and electrical, magnetic, and optical properties)

概要

論文の詳細を見る
Nanocrystals of La_<1-x>Sr_xMnO_<3+δ> (0<x≤0.51) with a diameter of about 8nm were synthesized in the pores of the mesoporous silica SBA-15. The crystal structure at all Sr concentrations had a rhombohedral symmetry. The temperature dependence of the magnetization showed ferromagnetic and superparamagnetic behavior, and the magnetization curves indicate the coexistence of a ferromagnetic and an antiferromagnetic component. ESR spectra were observed even at 77K and were well reproduced by the summation of two absorption lines with either a Gaussian or a Lorentzian profile. The temperature dependence in the ESR spectra suggests the coexistence of two components with two transition temperatures. The magnetic phase of the nanocrystals indicates the coexistence of a ferromagnetic and an antiferromagnetic phase at all Sr concentrations studied (0<x≤0.51), with a smooth Sr dependence of the two transition temperatures. The experimental results suggest the existence of a phase separation into a ferromagnetic and an antiferromagnetic state even in nanocrystals.
社団法人日本物理学会の論文
2008-07-15