Ferromagnetism and re-entrant spin-glass transition in quasicrystal approximants Au-SM-Gd (SM = Si, Ge).
JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013;
25:426004. [PMID:
24077450 DOI:
10.1088/0953-8984/25/42/426004]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Magnetic susceptibility and specific heat measurements on quasicrystalline approximants Au-Si-Gd and Au-Ge-Gd reveal that a ferromagnetic (FM) transition occurs at Tc = 22.5(5) K for Au-Si-Gd and at Tc = 13(1) K for Au-Ge-Gd, which are the first examples of ferromagnetism in crystalline approximants. In addition, a re-entrant spin-glass (RSG) transition is observed at TRSG = 3.3 K for Au-Ge-Gd in contrast to Au-Si-Gd. The different behaviors are understood based on the recent structural models reported by Gebresenbut et al (2013 J. Phys.: Condens. Matter 25 135402). The RSG transition in Au-Ge-Gd is attributed to a random occupation of the center of the Gd12 icosahedron by Gd atoms; a central Gd spin hinders the long-range FM order.
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