Double spin-glass-like behavior and antiferromagnetic superexchange interaction between Fe super(3+) ions in alpha -Ga sub(2-x)Fe sub(x)O sub(3) (0 [< or =] x [< or =] 0.4)

• Published in: Chinese physics B Vol. 24; no. 3; pp. 037502 - 1-037502-9
• Main Authors: Lv, Yi-Fei, Xiang, Jian-Yong, Wen, Fu-Sheng, Lv, Wei-Ming, Hu, Wen-Tao, Liu, Zhong-Yuan
• Format: Journal Article
• Language: English
• Published: 01.03.2015
• Subjects: Antiferromagnetism; Calorimetry; Diffraction; Direct current; Doping; Magnetic permeability; Magnetization; Reflectance; Spin glass
• DOI: 10.1088/1674-1056/24/3/037502
• ISSN: 1674-1056

Single phase of Fe super(3+)-doped alpha -Ga sub(2-x)Fe sub(x)O sub(3) ( alpha -GF sub(x)O, x = 0.1, 0.2, 0.3, 0.4) is synthesized by treating the beta -Ga sub(2-x)Fe sub(x)O sub(3) ( beta -GF sub(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 super(3+) content. Calorimetric measurements show that the temperature of the phase transition from alpha -GF sub(x)O to beta -GF sub(x)O increases, while the associated enthalpy change decreases upon increasing Fe super(3+) content. The optical energy gap deduced from the reflectance measurement is found to decrease monotonically with the increase in Fe super(3+) content. From the measurements of magnetic field-dependent magnetization and temperature-dependent inverse molar susceptibility, we find that the superexchange interaction between Fe super(3+) ions is antiferromagnetic. Remnant magnetization is observed in the Fe super(3+)-doped alpha -GF sub(x)O and is attributed to the spin glass in the magnetic sublattice. At high Fe super(3+) doping level (x = 0.4), two evident peaks are observed in the image part of the AC susceptibility chi " sub(ac). The frequency dependence in intensity of these two peaks as well as two spin freezing temperatures observed in the DC magnetization measurements of alpha -GF sub(0.4)O is suggested to be the behavior of two spin glasses.