Twenty million energy product samarium-cobalt magnet

Considerable interest has been centered around rare-earth-cobalt magnets during recent years. For the last two years we have been carrying out a research program in the general area of rare-earth-cobalt magnets. At this time, we have successfully developed a rare-earth-cobalt magnet with close to the attainable limit of magnetic properties. Our best magnets show the following properties:
B^{H}c
, 8000-9000 Oe;
M^{H}c
, 25 000 Oe; B
r
, 8000-9000 G;
(BH)_{\max}, 16-20 \times 10^{6}
G - Oe. The magnet is based on the rare-earth-cobalt compound RCo
5
, where R is samarium. Processing includes induction heat or arc melting, pulverizing to roughly domain size, compacting in hydraulic press in magnetic field to suitable shape and size, sintering, finishing, magnetizing, and stabilizing. Most of our laboratory production thus far has been ring magnets for PPM stacks of traveling wave tubes. These magnets have outperformed the best available platinum-cobalt magnets from both magnetic and thermal stability points of view in actual tube qualification tests.