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

Author(s)

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

• Document type: Journal article
• Source: PHYSICAL REVIEW B; v. 95, n. 10, p. 7-pg., 2017-03-08.

Abstract

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)

• FAPESP's process: 12/17562-9 - Preparation of oriented single crystals for studies on electronic, magnetic and thermal anisotropies
• Grantee: Marcos de Abreu Avila
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/19924-2 - Study and development of advanced novel materials: electronic, magnetic and nanostructured: an interdisciplinary approach
• Grantee: Carlos Rettori
• Support Opportunities: Research Projects - Thematic Grants