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RE: [femm] Temperature dependence of PM materials

The rare earth (Lanthanide for the purists) Gadolinium is ferromagnetic and has a Curie point around 16 degrees C. It's pretty soft magnetically though and would not make a permanent magnet but I did read somewhere that it had been used in alloys to reduce the Curie temperature.

Keith.

At 09:26 03/10/2002 -0600, you wrote: 
There are ferrites with curie point near room temperature.
Kirk

-----Original Message-----
From: Gal Janos [mailto:jgal@xxxxxxxxxx]
Sent: Thursday, October 03, 2002 4:03 AM
To: femm@xxxxxxxxxxxxxxx
Subject: RE: [femm] Temperature dependence of PM materials


Well, I can not suggest you PM material with strong temperature
dependence, maybe it is not exist.

Just an idea: how about to use soft magnet in the magnetic circuit,
which have the curie point at the required temperature. As I remember
the weller soldering tools are using the curie point of the insert to
regulate the temperature. A sort of inserts is available, with curie
point between 200 and 300 C. I know it is very high temperature for you,
but probably lower curie point materials are available.

Regards,

Janos

-----Eredeti üzenet-----
Feladó: David Meeker [mailto:dmeeker@xxxxxxxx]
Küldve: 2002. október 2. 19:17
Címzett: femm mailing list
Tárgy: [femm] Temperature dependence of PM materials

I'm looking at sort of an odd application in which it would be desirable

to have a PM material with a very strong temperature dependence.
Usually, the opposite is the desired property--one usually desires
magnetic materials that have as little temperature dependence as
possible so that small changes in operating temperature don't affect
machine performance. However, I'm curious to know if anyone has a
material in which the knee of the magnetization curve moves
significantly at fairly low temperatures, say in the 60C to 80C range.

Since this is sort of an odd requirement, I haven't been able to find
anything like this in my usual manufacturer's spec sheets and favorite
PM websites.

Dave.
--
David Meeker <http://femm.berlios.de/dmeeker>





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Dr. Keith Gregory
Senior Lecturer
Department of Electronic & Electrical Engineering
Loughborough University
Loughborough
Leicestershire
LE11 3TU
UK

Phone: +44 (0) 1509 227025 Fax: +44 (0) 1509 227014
Department web: http://www.lboro.ac.uk/departments/el/