Magnetic phase transition in ɛ-In x Fe2 − x O3 nanowires

Abstract

This paper reports on a study of magnetic properties of ordered arrays of ɛ-In x Fe2 − x O3 (x = 0.24) nanowires possessing a high room-temperature coercive force of 6 kOe. Lowering the temperature below 190 K brings about a sharp decrease of the coercive force and magnetization of nanowires driven by the magnetic phase transition from the ferrimagnetic into antiferromagnetic phase. The transition is accompanied by a decrease of the magnetic anisotropy constant, which accounts for the anomalous frequency dependence of the position of the maximum in the temperature dependence of dynamic magnetic susceptibility. In the low-temperature phase, a spin-flop transition in the magnetic field of 28 kOe has been observed at T = 2 K. Lines related to the high-temperature hard-magnetic and low-temperature phases have been identified in electron spin resonance spectra of the nanowires. A line lying near zero magnetic field and evolving from the nonresonant signal related to the microwave magnetoresistance of the sample has also been detected.