Mössbauer studies and inductive thermal properties of Mg x -doped maghemite nanoparticles

The Mg x -doped maghemite γ -Fe 2 O 3 ( x = 0.05, 0.10, 0.15, and 0.20) were investigated, with the aim of enhancing the magnetic hyperthermia properties. We precisely tuned the magnetic and thermal properties of Mg x -doped γ -Fe 2 O 3 prepared using a slightly modified high-temperature thermal decomposition method. The analysis of X-ray diffraction patterns confirmed the spinel phase, crystallite size, and lattice constant. Magnetization measurements performed on Mg x -doped γ -Fe 2 O 3 revealed that the magnetization was maximum for the x = 0.15 sample. Accordingly, this sample was exposed to plasma for 30 min. The thermal properties of Mg x -doped γ -Fe 2 O 3 were studied with temperature rise dependent on magnetic hyperthermia measurements under an externally applied magnetic field of 25 mT at 112 kHz. The change in magnetic properties before and after plasma treatment was investigated with Mössbauer spectroscopy and further analyzed with one sextet each for the tetrahedral A-site and octahedral B-site. The Fe ion state for each site was determined to be Fe 3+ at all temperatures. It was confirmed that the hyperfine magnetic field of the sample increased after plasma treatment.