Thin films of Ni ferrite and Ni-Zn ferrite are prepared by flash evaporation of ferrite particles and subsequent simple oxidation in an open electric furnace. The films are evaporated in a vacuum of 2±10
-5 mmHg onto substrates of glass and fused quartz plates maintained at room temperature. They are about from 500 to 14000Å in thickness. Their crystal structures and magnetic properties are carefully xvamined at each stage of oxidation process by electron diffraction and ferromagnetic resonance measurements, respectively. These results show that evaporated films are hardly composed of ferrite, so they had to be oxidized. Films of spinel structure are obtained by oxida-tion at 700°C for 8 hours in Ni ferrite and at 300°C for 4 hours or at 700°C for half an hour in Ni-Zn ferrite. In these films, saturation magnetization (4π
Ms) varies from 2200 to 2600 Gauss and
g-factor from 2.21 to 2.24 in Ni ferrite, and 4π
Ms from 3200 to 4700 Gauss and
g-factor from 1.98 to 2.14 in Ni-Zn ferrite. The half widths of the resonance
ΔH_??_ and
ΔH_??_ are measured by apply-ing d. c. field
H perpendicular and parallel to the film plane, respectively.
ΔH_??_ varies from 600 to 1000 Oe in Ni ferrite and from 400 to 1000 Oe in Ni-Zn ferrite, and
ΔH_??_ from 640 to 1000 Oe in Ni ferrite and from 400 to 800 Oe in Ni-Zn ferrite. The granular state of the film is examined electron microscopically.
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