Magnetic Properties and Mössbauer Studies of Fe₃O₄ Substituted with Gd Ions

Abstract

The Gd_0.05Fe_2.95O₄ nanoparticles were synthesized by seed - mediated growth and were reacted for 30, 45, 60 and 75 min (Gd₃₀, Gd₄₅, Gd₆₀ and Gd₇₅), respectively. The samples structural and magnetic properties were investigated by x-ray diffraction (XRD), vibrating sample magnetometry (VSM), and Mössbauer spectroscopy. The self-heating properties were investigated by using a MagneTherm device. According to XRD analysis, gadolinium (Gd) nanoparticles found to be a cubic spinel structure has a space group Fd-3m. The lattice constant (a0) of Gd nanoparticles are 8.3633 ˚A and increases to 8.3721 ˚A as the high-temperature reaction time increases. The particle size was determined using Scherrer’s equation and the maximum particle size was 10.84 nm. The maximum saturation magnetization (M_S) value of Gd₆₀ at room temperature was 63.10 emu/g. The self - heating temperature of Gd₆₀ at 112 kHz and 250 Oe was measured and 63.3 °C was the highest. Gd₆₀ had the largest particle size and highest M_S and self-heating properties were measured. Mössbauer measurements were performed to investigate hyperfine interactions at from 4.2 to 290 K.