1–370 GHz EPR Linewidths for K3CrO8: A Comprehensive Test for the Anderson–Weiss Model

摘要: Electron paramagnetic resonance (EPR) measurements have been carried out over the frequency range of 1-370 GHz on single crystals potassium peroxychromate (K3CrO8) with view examining current models exchange narrowing EPR signals in solids. K3CrO8 has a simple (tetragonal) lattice structure, can be grown as pure or diluted an isostructural diamagnetic host K3NbO8, and its paramagnetism described by very (S = 12, I 0) spin Hamiltonian. The were made at various orientations Zeeman field, emphasis principal directions g-tensor. For essentially all orientations, linewidth decreases monotonically for frequencies, omega0, from 1 to about 100 GHz, then starts increase higher omega0. In order delineate effects other sources line broadening, repeated system, K3NbO8 containing approximately/= 0.5 mole % K3CrO8, representing broadening effect magnetic field dependent terms, such due g-strain sample holder/waveguide magnetization high utilized, up 14 T. Using these data, linewidths analyzed terms three-dimensional systems. A reasonably good agreement was found Anderson-Weiss model, when modified effects. accuracy analysis procedure confirmed comparison presently determined values constant, J, dipolar Hp, their obtained dc susceptibility theoretical analysis, respectively; within 5% J (=1.35 K) 25% Hp (160 G). However, some deviations unusual splittings noted 370 whose origin remains unclear.