Kondo effect

Japanese: 近藤効果 - こんどうこうか（英語表記）Kondo effect

This is a phenomenon in which, when there are impurities with magnetic moments in a metal, the scattering of conduction electrons by these impurities becomes abnormally large at low temperatures. It has long been known that the electrical resistance of precious metals such as gold and platinum is minimal at low temperatures, unlike other metals. According to a theory proposed by Jun Kondo in 1964, conduction electrons undergo exchange interaction with the spin of the impurities, which causes the spin to flip and scatter. Because the spin of the impurities is a quantum mechanical property, the strength of scattering differs depending on the order in which the spin flips, and this difference results in a resistance proportional to log T ( T is the absolute temperature of the metal) at low temperatures, resulting in the phenomenon of a minimal resistance.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

金属中に磁気モーメントをもった不純物がある場合，この不純物による伝導電子の散乱が低温で異常に大きくなる現象。金や白金など貴金属の電気抵抗は，他の金属と違って低温で極小を示すことが古くから知られていた。近藤淳が 1964年に提唱した理論によれば，伝導電子は不純物のスピンと交換相互作用を行い，スピンは反転して散乱する。不純物のスピンは量子力学的なものなので，スピンが反転する順序によって散乱の強さが違い，その差から低温で log T ( T は金属の絶対温度) に比例する抵抗が現れて抵抗極小の現象を示すのである。

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