Microwave absorption dynamics in Fe3O4nanopowders around Verwey transition

Abstract

Abstract In Fe3O4 nanopowders were carried out microwave absorption measurements at X-band (8.8-9.8 GHz), in the 89-300 K temperature range, by means of the ferromagnetic resonance (FMR), the magnetically modulated microwave absorption spectroscopy (MAMMAS) and the low-field microwave absorption (LFMA). The Verwey transition around Tv ∼ 137 K has been detected employed the FMR parameters: the resonant field (Hres ) and the linewidth (ΔHpp ), as temperature function. MAMMAS response shows features that can also be associated with Verwey transition. Finally, LFMA spectra are associated with a magnetic state in Fe3O4 nanopowders, where a lineal component with positive slope and a hysteresis loop around zero magnetic field are clearly observed, and behavior in temperature of the lineal component also suggests the presence of the Verwey transition.