D. Givord, Grenoble
(Laboratoire Louis Néel, C.N.R.S.I
I — From AINiCo's to Neodymium-IronBoron Permanent Magnets
In several instances, since the beginning of this century, the discovery of new
magnetic materials has strongly influenced the development of permanent magnets. The first very important advance
was made in 1932 in Japan. Mishima
prepared magnets by thermal treatment
of an alloy based on iron, nickel and
aluminium, that led to a new range of
alloys now known as AINiCo. The
energy product attained was an order of
magnitude larger than that of any previously known magnetic material. In
1953, low cost ferrites were discovered
in the Philips laboratories. These have
the remarkable property of being strongly resistant to induction fields which
tend to reverse the magnetic moment,
i.e. they have a high coercivity
https://www.europhysicsnews.org/articles/epn/pdf/1987/07/epn19871807p93.pdf
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