ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Transparent iron-oxide films were fabricated by sol-gel synthesis using a solution of ferric nitrate (III) dissolved in ethylene glycol.1 The solution was kept at 80 °C and stirred constantly in a nitrogen atmosphere. The gel with an appropriate viscosity was spin coated on soft glass plates, then dried and heated in air at various temperatures for 5 h. The films thus prepared are about 0.2 μm thick, amber colored, and especially transparent in the near-infrared region, whose transmittance exceeds 90%. Maximum saturation magnetization 4πMs=0.74 kG [curve (a)] was obtained by annealing at 450 °C, which is still insufficient to use practical application. Reduction heat treatment in a hydrogen atmosphere is found to be very effective to improve magnetic properties: 4πMs is increased to 3 kG [curve (b)], which is about four times as large as the previous one, but the films become semitransparent due to formation of magnetite particles. Original high transmittance recovers by successive annealing in air at 400 °C without any degradation of magnetic properties [curve (c)], where diffraction peaks of maghemite were observed. This strongly suggests that magnetic anisotropy may be arbitrarily controlled by forming linear chains of ferromagnetic particle clusters through reduction heat treatment in a magnetic field. Faraday rotation θF of the samples was also measured. These films are promising as a new type magneto-optic material.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.342345
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