Electromagnet with high remanence

[ashare]

I am in search of an electromagnet which has high magnetic remanence (or retentivity) even when the current through the electromagnet is zero. Can someone provide information about such a material?

 

[mfb]

Which size and field strength are you looking for?
What about combining a permanent magnet with an electromagnet?

 

[ashare]

At the moment, I don't have a specific number to give you regarding the size and strength. The smaller the better. This electromagnet will be interacting with the field of another permanent magnet which will be attached to another structure. My requirement is to alter the field of the electromagnet by varying the current through it. However, I want the electromagnet to maintain the magnetism even after I remove the electric current.

 

[mfb]

The smaller the better.

Really? Do you want micrometer-sized electromagnets?

Engineering problems depend on the scale. If you want to do something with a size of a few micrometers, it will look completely different from huge electromagnets with a size of a meter or more. Currently there is no scale given at all.

 

[ashare]

I understand. I am not looking for a micrometer scale magnet. A few millimiter (10-20 mm) should be good enough.