Synthesis and Moessbauer Study of Maghemite Nanowire Arrays

摘要

Arrays of γ-Fe_2O_3 nanowire were synthesized in anodic aluminum oxide templates. The structure, morphology and magnetic property at room temperature were characterized. Temperature-dependent Moessbauer spectra was collected and the superparamagnetic relaxation was clearly observed. Both hyperfine field and isomer shift increase with decreasing temperature. The anisotropy energy constant is determined from the reduction of the hyperfine field relative to the saturation value caused by the collective magnetic excitations.