Dynamic Magnetic Properties of La0.8Ag0.2MnO3 Nanoparticles

In thisresearch,nanoparticlesof La0.8Ag0.2MnO3 with mean particle sizes d of 16 and 22 nm have been prepared by sol-gel method. Dynamic magnetic properties of the samples have been carried out by AC magnetic susceptibility and electron spin resonance techniques. The structural properties of the samples have been characterized by X-ray diffraction using Rietveld refinement and transmission electron microscopy. The analysis of the AC magnetic susceptibility by phenomenological models reveals the interacting superparamagnetic behaviors in La0.8Ag0.2MnO3 nanoparticles. From the Vogel-Fulcher model, the values of 1.3 x 10(4) and 2.8 x 10(4) erg/cm(3) are obtained for the effective magnetic anisotropy constant for d= 16 and 21 nm, respectively. Electron spin resonance signals of the samples are well described by double Lorentzian line shapes which suggest the presence of ferromagnetic clusters in the paramagnetic phase and possible phase separation at room temperature.