Magnetics ZH42206TC toroid core

[ivconic]

bad idea, I believed that mumetal and permalloy have similar mechanical properties, and permalloy is specially heated after mechanical processing....

Yes I experienced lot of troubles trying to cut and straighten them. Wasted many pieces like that.
It didn't occur to me to heat it with hot air soldering tool and try like that.
Anyway ; toroid core is much easier to handle and set the windings on it.
So I am still for toroid cores. Makes my life much easier.

[pito]

contact producers directly on alibaba.com, some of them offer samples.
https://www.alibaba.com/product-detail/High-Permeability-MingDa-Ferrite-Core-Toroid_60417822195.html?spm=a2700.galleryofferlist .normal_offer.d_price.1e8feeb54dkKWG

[Krzysztof]

The mumetal material is cold-rolled and any attempts to cut cause changes in physical properties, including magnetic permeability and Curie temperature - the sample becomes unstable and unpredictable; This also applies to anti-theft tags.
I've experienced this firsthand. You're left with a toroid or the use of tags in the form of straight cores, but beware - they can't be pressed.

[ivconic]

The mumetal material is cold-rolled and any attempts to cut cause changes in physical properties, including magnetic permeability and Curie temperature - the sample becomes unstable and unpredictable; This also applies to anti-theft tags.
I've experienced this firsthand. You're left with a toroid or the use of tags in the form of straight cores, but beware - they can't be pressed.

Good info, thanks!
Although I didn't know that; I instinctively gravitated towards toroid solutions anyway.