Spin-glass properties of metallic nanoparticles conducted by quantum size effects

Abstract

Diamagnetic silver reveals spin-glass properties as the material is dispersed into nanoparticles embedded in dielectric media. Significant shifts of the transition temperature ${T}_{\mathrm{SG}}$ toward high temperatures with the filling factor are observed during the zero-field-cooling process for the magnetic susceptibility $\ensuremath{\chi}(T)$ measurement. The diffused quantum-sphere model is exploited to calculate the susceptibility of nanoparticles containing even or odd numbers of electrons in terms of particle sizes, which manifests a paramagnetic Curie-like characteristic as the temperature rises above ${T}_{\mathrm{SG}}.$ The partition function evaluated by the spin-glass magnetic-dipole interaction conducted by quantum size effects can successfully address the experimental data with good quantitative agreement.