Temperature dependence of magnetic hysteresis of RCox : Co nanocomposites (R=Pr and Sm)

The temperature dependence of magnetic hysteresis of RCox:Co (R=Pr and Sm) nanocomposite films is reported. These films are prepared by dc and rf sput tering and subsequent thermal processing. It is found that the squareness o f the hysteresis loops deteriorates with decreasing temperature. This is at tributed to the enhanced magnetic anisotropy of the hard phases at low temp eratures. The analysis of the magnetic reversal process shows that the anis otropy enhancement leads to a transition from cooperated to independent beh avior. This analysis agrees well with the experimental results. (C) 2000 Am erican Institute of Physics. [S0021-8979(00)24708-7].