Who invented ferrite?

Who invented magnetic core material known as ferrite?

• Dr. Takeshi Takei from the Tokyo Institute of Technology, discovered zinc and iron oxides have special magnetic properties.
• Professors Kato and Takei applied for a patent in Japan in 1930 for their discovery of oxide magnetic core materials which was granted in 1932.
• Tokyo Denki Kagaku Kogyo (now known as TDK Corporation) was founded in 1935 to commercialize ferrite cores.  TDK is still making ferrite cores today.
• Philips applied for a patent in The Netherlands in 1941 for ferrite.

Ferrite Bead

Good DX and 73, NJ2X