Soft magnetic ferrites (Kato and Takei)
Ferritas magnéticas blandas (Kato y Takei)
- Date
- 1930-1946 · confidence high
- Place
- Tokyo, Japan
- Credited to
- Yogoro Kato and Takeshi Takei; later Jacob Snoek (Philips)
- Field
- Matter & energy
⚠️ Disputed: the sources disagree.
What it is
Ceramic iron oxides with zinc or nickel that are soft magnets and electrical insulators, so they have almost no eddy-current losses. They are the core of high-frequency transformers and coils.
Kato and Takei patented ferrites in Japan in 1930 and founded TDK in 1935; Snoek developed them at Philips (Eindhoven) from 1936 and industrialised them after the war. The credit varies.
What it led to
- cores for switching power supplies and radio transformers
- the founding of TDK (1935) to make them
- ferrite antennas and core memory