title: Geometric origin of magnetic frustration in the μ-Al₄Mn giant-unit-cell complex intermetallic.
abstract: The structurally ordered μ-Al(4)Mn complex intermetallic phase with 563 atoms in the giant unit cell shows the typical broken-ergodicity phenomena of a magnetically frustrated spin system. The low-field zero-field-cooled and field-cooled magnetic susceptibilities show splitting below the spin freezing temperature T(f) = 2.7 K. The ac susceptibility exhibits a frequency-dependent cusp, associated with a frequency-dependent freezing temperature T(f)(ν). The decay of the thermoremnant magnetization is logarithmically slow in time and shows a dependence on the aging time t(w) and the cooling field H(fc) typical of an ultraslow out-of-equilibrium dynamics of a nonergodic spin system that approaches thermal equilibrium, but can never reach it on the experimentally accessible time scale. The above features classify the μ-Al(4)Mn complex intermettalic among spin glasses. The origin of frustration of magnetic interactions was found to be geometrical due to the distribution of a significant fraction of Mn spins on triangles with antiferromagnetic coupling. The μ-Al(4)Mn phase is a geometrically frustrated spin glass.
authors.affiliation: J Stefan Institute, University of Ljubljana, Jamova 39, SI-1000 Ljubljana, Slovenia.
authors.forename: S
authors.initials: S
authors.lastname: Jazbec
authors.forename: Z
authors.initials: Z
authors.lastname: Jagličić
authors.forename: S
authors.initials: S
authors.lastname: Vrtnik
authors.forename: M
authors.initials: M
authors.lastname: Wencka
authors.forename: M
authors.initials: M
authors.lastname: Feuerbacher
authors.forename: M
authors.initials: M
authors.lastname: Heggen
authors.forename: S
authors.initials: S
authors.lastname: Roitsch
authors.forename: J
authors.initials: J
authors.lastname: Dolinšek