Superparamagnetic relaxation in Cu_{x}Fe_{3-x}O_{4} (x=0.5 and x=1) nanoparticles

摘要

The scope of this article is to report very detailed results of themeasurements of magnetic relaxation phenomena in the newCu$_{0.5}$Fe$_{2.5}$O$_{4}$ nanoparticles and known CuFe$_{2}$O$_{4}$nanoparticles. The size of synthesized particles is (6.5$\pm $1.5)nm. Bothsamples show the superparamagnetic behaviour, with the well-defined phenomenaof blocking of magnetic moment. This includes the splitting ofzero-field-cooled and field-cooled magnetic moment curves, dynamicalhysteresis, slow quasi-logarithmic relaxation of magnetic moment below blockingtemperature. The scaling of the magnetic moment relaxation data at differenttemperatures confirms the applicability of the simple thermal relaxation model.The two copper-ferrites with similar structures show significantly differentmagnetic anisotropy density and other magnetic properties. Investigated systemsexhibit the consistency of all obtained results.