The hard-magnetic properties of rare earth-transition metal alloys

Abstract

The intermetallic phases formed between the rare earth metals (R) and the elements of the 3-d transition series are a large group of new substances with interesting magnetic properties. They have been studied intensely in the last decade. Their properties are reviewed with a view toward their usefulness for permanent magnets. Some aspects of the recently developed magnets based on certain RCo <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> compounds are discussed. The prediction is made that second-generation rare earth magnets can be developed using R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (Co,Fe) <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">17</inf> alloys. These should have energy products and thermal stability superior even to sintered SmCo <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> , while being less expensive. Experimental evidence supporting this claim is discussed.