Variations in temperature coefficient of anisotropy and coercivity in finite particles of Nd/sub 2/Fe/sub 14/B type recording materials through substitutions

A theoretical and experimental study is reported on how to modify the temperature dependence of coercivity, H/sub c/(T), in R/sub 2/F/sub 14/B type compounds (R=rare earth) through modifications of the temperature dependence of anisotropy field, H/sub A/(T). This is accomplished by partial substitutions on R sites. Experimentally it is found that for Y/sub 2/Fe/sub 14/B fine particles ( approximately 1- mu m), values of H/sub c/ are in the range of 1 kOe. For these materials, a slightly positive H/sub c/(T) is obtained near 300 K. Stable H/sub A/(T) and H/sub C/(T) near 300 K are obtained, e.g., with Nd/sub 0.2/Y/sub 0.8/Fe/sub 14/B, while strongly increasing H/sub A/(T) and H/sub c/(T) are obtained with small substitutions of Er for Y in Y/sub 2/Fe/sub 14/B. More complex H/sub A/(T) and H/sub c/(T) can be obtained in more complex systems.<>