Conduction electrons mediating the evolution from antiferromagnetic to ferromagnetic ordering in Gd(Co1-yFey)(2)Zn-20 (0 <= y <= 1)

Autor(es)

Cabrera-Baez, M. ; Naranjo-Uribe, A. ; Osorio-Guillen, J. M. ; Rettori, C. ; Avila, M. A.

• Tipo de documento: Artigo Científico
• Fonte: PHYSICAL REVIEW B; v. 95, n. 10, p. 7-pg., 2017-03-08.

Resumo

GdFe2Zn20 is a complex cagelike compound with an unusually high ferromagnetic ordering temperature (T-C = 86 K) for a very diluted Gd3+ magnetic sublattice, embedded in a matrix that features strong electronelectron correlations. Here, we report on a magnetic and electronic study of the substitutional intermetallic system Gd(Co1-y Fe-y)(2)Zn-20 combining magnetizationmeasurements plus first-principles density functional theory (DFT) calculations with temperature-dependent electron spin resonance (ESR). After accounting for electron-electron correlations and itinerant molecular field effects, the ESR results indicate that the exchange interaction between the Gd3+ is processed via a single band of d-type electrons at the Fermi level and the exchange interaction is covalent in nature [J(0)(fd) < 0] with a strong conduction electron (ce) momentum transfer dependence [Jfd (q)]. The DFT calculations support this scenario by indicating a major contribution of d-type ce at the Fermi level and a spin polarization in (Y, Gd) Fe2Zn20 wherein the most stable configuration is antiferromagnetic between Gd3+ and ce spins. Our results demonstrate that the standard Ruderman-Kittel-Kasuya-Yosida mechanism cannot explain the ferromagnetic behavior of GdFe2Zn20 and a superexchangelike mechanism is proposed for this magnetic interaction. An "extended phase diagram" for the double substitution sequence YCo2Zn20. GdCo2Zn20. GdFe2Zn20 is presented and discussed. (AU)

• Processo FAPESP: 12/17562-9 - Preparação de monocristais orientados para estudos de anisotropias eletrônicas, magnéticas e térmicas
• Beneficiário: Marcos de Abreu Avila
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 11/19924-2 - Estudo e desenvolvimento de novos materiais avançados: eletrônicos, magnéticos e nanoestruturados: uma abordagem interdisciplinar
• Beneficiário: Carlos Rettori
• Modalidade de apoio: Auxílio à Pesquisa - Temático