Saw on eBay today:
"Metglass, nanocrystaline tape 25mm wide, 34 microns thick. lso different width 30mm, 40mm. It can go to 50kHz at 1.2T or even up to 200kHz with less flux. People use it for high efficiency generators and cores for MEGs and Miller's generators and high efficiency transformers."
http://cgi.ebay.ca/Metglass-nanocrystalline-tape-for-MEG-generator-5kg_W0QQitemZ250043736539QQihZ015QQcategoryZ1267QQcmdZViewItem (http://cgi.ebay.ca/Metglass-nanocrystalline-tape-for-MEG-generator-5kg_W0QQitemZ250043736539QQihZ015QQcategoryZ1267QQcmdZViewItem)
That looks very interesting. I'm wondering if the seller has any more info on the material such as where he got the tape, the name of the material, etc.
Paul Lowrance