Double spin-glass-like behavior and antiferromagnetic superexchange interaction between Fe^(3+) ions in α-Ga_(2-x)Fe_xO_3(0≤x≤0.4)  

作　　者：吕益飞 向建勇 温福昇 吕伟明 胡文涛 柳忠元 

机构地区：[1]State Key Lab of Metastable Materials Science & Technology,Yanshan University

出　　处：《Chinese Physics B》2015年第3期336-344,共9页中国物理B（英文版）

基　　金：supported by the National Basic Research Program of China(Grant No.2010CB731605);the National Science Fund for Distinguished Young Scholars of China(Grant No.51025103);the National Natural Science Foundation of China(Grant Nos.51172198 and 51102206);the Natural Science Foundation of Hebei Province,China(Grant No.E2014203144);the Science Foundation for the Excellent Youth Scholars from Universities and Colleges of Hebei Province,China(Grant No.YQ2014009);the Research Program of the College Science&Technology of Hebei Province,China(Grant No.QN2014047)

摘　　要：Single phase of Fe^3＋-doped α-Ga2-xFexO3（α-GF x O, x = 0.1, 0.2, 0.3, 0.4） is synthesized by treating the β-Ga2-x Fe x O3（β-GF x O） precursors at high temperatures and high pressures. Rietveld refinements of the X-ray diffraction data show that the lattice constants increase monotonically with the increase of Fe^3＋content. Calorimetric measurements show that the temperature of the phase transition from α-GF x O to β-GF x O increases, while the associated enthalpy change decreases upon increasing Fe^3＋content. The optical energy gap deduced from the reflectance measurement is found to decrease monotonically with the increase in Fe3＋content. From the measurements of magnetic field-dependent magnetization and temperature-dependent inverse molar susceptibility, we find that the superexchange interaction between Fe^3＋ions is antiferromagnetic. Remnant magnetization is observed in the Fe^3＋-doped α-GF x O and is attributed to the spin glass in the magnetic sublattice. At high Fe^3＋doping level（x = 0.4）, two evident peaks are observed in the image part of the AC susceptibility χ ac. The frequency dependence in intensity of these two peaks as well as two spin freezing temperatures observed in the DC magnetization measurements of α-GF0.4O is suggested to be the behavior of two spin glasses.Single phase of Fe^3＋-doped α-Ga2-xFexO3（α-GF x O, x = 0.1, 0.2, 0.3, 0.4） is synthesized by treating the β-Ga2-x Fe x O3（β-GF x O） precursors at high temperatures and high pressures. Rietveld refinements of the X-ray diffraction data show that the lattice constants increase monotonically with the increase of Fe^3＋content. Calorimetric measurements show that the temperature of the phase transition from α-GF x O to β-GF x O increases, while the associated enthalpy change decreases upon increasing Fe^3＋content. The optical energy gap deduced from the reflectance measurement is found to decrease monotonically with the increase in Fe3＋content. From the measurements of magnetic field-dependent magnetization and temperature-dependent inverse molar susceptibility, we find that the superexchange interaction between Fe^3＋ions is antiferromagnetic. Remnant magnetization is observed in the Fe^3＋-doped α-GF x O and is attributed to the spin glass in the magnetic sublattice. At high Fe^3＋doping level（x = 0.4）, two evident peaks are observed in the image part of the AC susceptibility χ ac. The frequency dependence in intensity of these two peaks as well as two spin freezing temperatures observed in the DC magnetization measurements of α-GF0.4O is suggested to be the behavior of two spin glasses.

关 键 词：α-Ga2O3 susceptibility superexchange interaction spin glass 

分 类 号：O469[理学—凝聚态物理]