Exchange Interaction in the Co-SiO2 Nanocomposite Films
The properties of Co-SiO2 nanogranular composite films, containing a Co volume fraction ranging from 0.3 to 0.8, have been characterized by means of magnetic measurements, NMR study, and ferromagnetic resonance. Thermal decrease of CoX(SiO2)100-X magnetization follows the T3/2 law and allows to estimate the exchange interaction constant A. With growing nominal Co content the transitions from granular to continuous structural state at 36% Co are registered by FMR measurements. The spectrum of standing spin-wave has been detected in the perpendicular experiment configuration for films with the Co content above 52 vol. %. It is found that the type of the dispersion relation of spin waves in Co-SiO2 composite films is affected by the exchange coupling fluctuations.
E. A. Denisova et al., "Exchange Interaction in the Co-SiO2 Nanocomposite Films", Solid State Phenomena, Vols. 168-169, pp. 265-268, 2011