- 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.
Good DX and 73, NJ2X