Ferromagnetism in Fe-doped Ba6Ge25 Chiral Clathrate

Abstract

We have successfully synthesized a Ba6Ge25 clathrate, substituting 3 Fe per formula unit by Ge. This chiral clathrate has Ge sites forming a framework of closed cages and helical tunnel networks. Fe atoms randomly occupy these sites, and exhibit high-spin magnetic moments. A ferromagnetic transition is observed with Tc = 170 K, the highest observed Tc for a magnetic clathrate. However, the magnetic phase is significantly disordered, and exhibits a transformation to a re-entrant spin glass phase. This system has a number of features in common with other dilute magnetic semiconductors.

Submitted to Applied Physics Letters. Fig. 1 resolution reduced for online archive version

References in corpus (3)

• Temperature-dependent magnetization in diluted magnetic semiconductors
• Noncollinear Ferromagnetism in (III,Mn)V Semiconductors
• Band structure calculations for Ba${}_6$Ge${}_{25}$ and Ba${}_4$Na${}_2$Ge${}_{25}$ clathrates

Cited by in corpus (2)

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• Magnetic properties of Mn-doped Ge46 and Ba8Ge46 clathrates