Magnetic Ordering of CoCl2-GIC: a Spin Ceramic -Hierarchical Successive Transitions and the Intermediate Glassy Phase-
نویسندگان
چکیده
Stage-2 CoCl2-GIC is a spin ceramic and shows hierarchical successive transitions at Tcu (= 8.9 K) and Tcl (= 7.0 K) from the paramagnetic phase into an intra-cluster (two-dimensional ferromagnetic) order with inter-cluster disorder and then to an inter-cluster (three-dimensional antiferromagnetic like) order over the whole system. The nature of the inter-cluster disorder was suggested to be of spin glass by nonlinear magnetic response analyses around Tcu and by studies on dynamical aspects of ordering between Tcu and Tcl. Here, we present a further extensive examination of a series of time dependence of zero-field cooled magnetization MZFC after the aging protocol below Tcu. The time dependence of the relaxation rates SZFC(t) = (1/H)dMZFC(t)/d ln t dramatically changes from the curves of simple spin glass aging effect below Tcl to those of two peaks above Tcl. The characteristic relaxation behavior apparently indicates that there coexist two different kinds of glassy correlated regions below Tcu. PACS numbers: 75.40.Gb, 75.50.Lk, 75.30.Kz, 75.30.GW § [email protected] ‖ [email protected]
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