Owen Duffy wrote in
:

....
Search Jaycar's site for a LO1238. If that is what you have, you could
ask them for data.

I should have added that I think it is similar to the L8 material described
in their data sheets.

I have a vague recollection of measuring the inductance of a winding on the
material, and I think the ui was around 1500 which suggests it is low loss
up to a few hundred kHz, perhaps to 1MHz or so.

Owen