Temperature dependence of the coercive force of ferromagnetic TM-Al-O (TM=Fe, Co) granular films

The temperature dependence of the coercive force (H c ) of ferromagnetic TM-Al-O (TM=Fe, Co) granular films has been investigated in the temperature range from 290 down to 2 K. Fe-Al-O films show weak anisotropy. In contrast, Co-Al-O films show clear in-plain anisotropy. The coercive forces of Co-Al-O films show a logarithmic temperature dependence at low temperatures while those of Fe-Al-O films are almost independent of temperature.