Paramagnetic tunneling state concept of the low-temperature magnetic anomalies of multicomponent insulating glasses

A generalized tunneling model of multicomponent insulating glasses is formulated, considering a subset of tunneling states to be paramagnetic centers of the electronic hole type. The expression for magnetic field-dependent contribution into the free energy is obtained. The derivation is made of the expression for the nonmonotonic magnetic field dependence of dielectric susceptibility, recently observed for some SiO2-based glasses in the sub-Kelvin temperature range. (c) 2006 Elsevier B.V. All rights reserved.