Ruderman-Kittel-Kasuya-Yosida mechanism

The incompletely filled 4f-shell confers a magnetic moment to the lanthanide ions and it is the Ruderman-Kittel-Kasuya-Yosida (RKKY) mechanism via polarization of the conduction electrons which is responsible for the occurrence of long-range ordered magnetic structures in the lanthanide metals. Details can be foimd in numerous reviews, among others in vol. 1, chs. 3, 6 and 7 (1978) of this Handbook series and a recent one by Jensen and Mackintosh (1991). The addition of hydrogen, both in solution or resulting in hydride formation, leads to a decrease of the conduction electron density e (cf. sect. 5)... 

Zener gave rise to appear two main approaches. The first is double exchange (DE) mechanism in the sense of Anderson and Hasegawa [6]. The second is the mechanism of indirect interaction by Ruderman-Kittel-Kasuya-Yosida (RKKY) [25-27]. 

In metallic systems with 4f atoms the most prominent source of long-range interaction between magnetic moments is the mechanism first described by Ruderman and Kittel (1954), Kasuya (1956) and Yosida (1957), which involves the conduction-electron sea as mediator of the interaction. Distinctive features of the RKKY-interactions are its long range and oscillatory nature ... 

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