NMR Study of the Dimerized State in CuIr2S4

Abstract

VI/e have investigated the metal-insulat.or transition crvnT) 0[' CuTr 2 S1 b,Y a high resolut.ion :"J1 ... TR measurement. The Cu-NT\fR spectrum below T,'dl is broadened and split int.o ['our eu signals with sizable electric quadrupole interactions. The NT\fR results are consistent \vit.h t.he charge ordering of lr 31 and lr'il and the ~pin dilllerization of lr'il spins, as revealed by a recent X-ray study.keyvmrds: ~\J1'vlH" llletal~insulator transition, spinel, CUir2 S4

Magnetic Frustration in Iridium Spinel CompoundCuIr2S4

“…It should be noted that the occurrence of weak magnetism has been already hinted in some of the earlier literatures. For example, the spin-lattice relaxation rate (1/T 1 ) versus temperature (T ) plot in an earlier report of 63 Cu-NMR studies exhibits an unusual power law, (T 1 T ) −1 ∝ T 2 in the insulating phase where thermal activation behavior (∝ e −W/kB T , with W being the band gap) would be anticipated [16]. While this peculiar result is currently attributed to an anisotropic band structure, it may suggest the absence of the excitation gap expected for the spin-Peierls state.…”

“…in the insulating phase where thermal activation behavior (∝ e −W/kB T , with W being the band gap) would be anticipated [16]. While this peculiar result is currently attributed to an anisotropic band structure, it may suggest the absence of the excitation gap expected for the spin-Peierls state.…”