Ferrimagnetic Resonance in Copper Ferrite, I. Cubic-Phase Single Crystal

The ferrimagnetic resonance in a cubic phase single crystal of CuFe 2 O 4 was measured with an X-band spectrometer from 77°K to 300°K. At room temperature, K 1 / M (the 1'st order cubic anisotropy field) and g eff (effective g-value) are -172 Oe and 2.09, respectively. At liquid nitrogen temperature, they are -810 Oe and 2.44. The half line width is maximum (85 Oe at RT) around [100] (a hard direction of magnetization). K 1 / M extraporated down to 0°K is about -900 Oe and K 1 (0°K) is -9.7×10 -2 cm -1 per molecule. This value of K 1 (0°K) may be understood as arising from the single ion anisotropy of Fe 3+ due to cubic crystal field splitting, and a value of a B (Fe 3+ ) (fine structure constant of Fe 3+ on B-site in cubic crystal field) derived under some assumptions is +2.8×10 -2 cm -1 .