High energy product, temperature compensated permanent magnets for device use at high operating temperatures

The coercivity, remanence, energy product, and temperature coefficients of remanence and energy product have been determined for permanent magnet specimens of the form Sm(1-x)Er(x)(Co,Fe,Cu,Zr)7.22 in the temperature range 200-800 K. A comparison of the results obtained with the available data for SmCo5 and Sm2Co17 shows that all the materials tested in the present study are better suited for applications above 400 K. Of the samples tested, Sm0.6Er0.4(Fe,Co,Cu,Zr)7.22 is found to be the most promising permanent magnet material for high-temperature use. At 500 K, it has a remanence of 9.3 kG, an intrinsic coercivity of 9.4 kOe, an energy product of 16.5 MGOe, and temperature coefficients of remanence and energy product of 0.004 and 0.008 pct/K, respectively.