Temperature coefficients of rare earth permanent magnets

A new approach for calculating the temperature coefficients of magnetic parameters is proposed in order to more accurately describe high temperature characteristics of magnetic materials. Using this new approach, the "true" (or instantaneous) temperature coefficient of any magnetic parameter at a specific temperature can be determined and a plot of temperature coefficient vs. temperature can be obtained. This new type of plot is a very useful tool to present temperature characteristics of a magnetic parameter. Data of temperature coefficient as a function of temperature for magnetization, intrinsic coercivity and maximum energy product are given for several types of rare earth permanent magnets. By applying the same approach, the temperature coefficients of heavy rare earth substituted magnets are calculated for (Sm/sub 1-x/Gd/sub x/)Co/sub 5/ and (Sm/sub 1-x/Gd/sub x/)/sub 2/TM/sub 17/ systems with 0/spl les/x/spl les/1.