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We investigated the anomalous Hall effect and longitudinal magnetoresistance in ferrimagnetic Co90Gd10 thin films with thicknesses from 5 to 35 nm and temperatures from 80 to 300 K. As the temperature increases from 80 to 300 K, the saturation magnetization of Co90Gd10 increases from 720 to 844 emu/cm3. However, the scaling law \sigma xy – \sigma xx^{n} with $n =2.3$ holds surprisingly well. Our results indicate that the scaling law usually reported in ferromagnetic materials remains valid for ferrimagnetic materials, which undoubtedly suggested the universality of the scaling law. [ABSTRACT FROM AUTHOR]

We report a comparative study of magnetic and magnetoabsorption properties of bulk and nanoparticles of Ga2-xFe_xO3 (x\approx 1.25) compounds synthesized using sol-gel method. The average size of Ga2-xFe_xO3 nanoparticles is found to be 100 nm. We observe an enhancement in the ferrimagnetic transition temperature (TC=354\ K) of Ga2-xFe_xO3 nanoparticles compared to TC=298\ K of the bulk Ga2-xFe_xO3. The bulk and nanoparticles of Ga2-xFe_xO3 exhibit a large coercive field (HC) of HC= 0.95 and 0.8 T at T= 10 K, respectively and we observe that the HC decreases dramatically with increasing temperature. Magnetoabsorption was studied with a LC resonance technique and we found a close correlation between the shift in the resonance frequency due to applied magnetic field and the coercive field measured using dc magnetization measurements. We discuss the possible origins of the observed effects in both bulk and nanoparticles of Ga2-xFe_xO3 compounds. [ABSTRACT FROM AUTHOR]