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

TL;DR

This paper introduces a generalized tunneling model for multicomponent insulating glasses, explaining low-temperature magnetic anomalies by considering paramagnetic tunneling states, and derives expressions for magnetic field effects on free energy and dielectric susceptibility.

Contribution

It presents a novel model that accounts for magnetic anomalies in glasses by incorporating paramagnetic tunneling states, extending previous tunneling models.

Findings

Derived magnetic field dependent free energy expression

Explained nonmonotonic dielectric susceptibility behavior

Applied model to amorphous BaO-Al2O3-SiO2 glasses

Abstract

A generalized tunneling model of multicomponent insulating glasses is formulated, considering 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 in amorphous BaO-Al_2O_3-SiO_2 in sub-Kelvin temperature range.