Ferromagnetism in Fe-doped Ba[sub 6]Ge[sub 25] chiral clathrate

Yang Li; Ross Jr., Joseph H.
October 2003
Applied Physics Letters;10/6/2003, Vol. 83 Issue 14, p2868
Academic Journal
We have synthesized a Ba[sub 6]Ge[sub 25] clathrate, substituting 3 Ge per formula unit by Fe. 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 T[sub c]=170 K, the highest observed T[sub c] for a magnetic clathrate. However, the magnetic phase is significantly disordered, and exhibits a transformation to a reentrant spin glass phase. This system has a number of features in common with other dilute magnetic semiconductors. © 2003 American Institute of Physics.


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