Mg_<1+x>Fe_<2-2x>Ti_xO_4(0≦x≦0.5)のキュリー温度と磁気交換相互作用(磁性体物理・超伝導)

概要

論文の詳細を見る
The magnetic properties of a low-Curie-temperature Mg_<1+1>Fe_<2-2x>Ti_xO_4 system, which could be used in magnetic induction hyperthermia, were investigated. The thermo-magnetization curves and magnetic susceptibilities at high temperatures for water-quenched and slow-cooled Mg_<1+1>Fe_<2-2x>Ti_xO_4 samples were measured. The Curie temperature decreased with increasing Ti concentration x and increasing cooling rate. Rietvelt analysis was performed to determine the site occupancy at A and B sites of the constituent atoms in the spinel structure. The exchange interactions, J_<AB>, J_<AA>,and J_<BB>, were then estimated by molecular field theory. The calculated Curie temperatures as a function of x and those for samples with different heat treatments were in good agreement with experimental data. The effect of the inter-atomic angle Φ between Fe-O-Fe on the Curie temperature was also investigated under the super-exchange interaction regime. The reduction of the super-exchange interaction owing to the increase in angle Φ contributes to the decrease of the Curie temperature.
社団法人日本磁気学会の論文
2006-03-01