Properties of Amorphous Magnetic Oxides Reduced by H2

The characteristics of Fe
₃
O
₄
-CaO-SiO
₂
amorphous magnetic oxides when heat-treated in an H
₂
atmosphere are discussed. The magnetization rose with the heat-treatment temperature and peaked at 60 emu/g at 900°C, with the CaSiO
₃
phase precipitating in the neighborhood of 650°C. This magnetization increase was proportional to the applied magnetic field increase. The failure of film samples to saturate completely even at 7 kOe indicated small precipitated Fe particles and high resistivity which were measured in some samples at 0.05 ~ 0.2 μm and 4 × 10
⁶
Ω-cm, respectively.