Magnetic properties, relaxation, and quantum tunneling i nanoparticles embedded in potassium silicate

Abstract

We report magnetic properties and magnetic relaxation phenomena in a sample comprised of nanocrystalline (Formula presented)(Formula presented) (∼97%)+γ-(Formula presented)(Formula presented) (∼3%) and polymer in potassium silicate (as magnetic glass) nanoparticle systems in which two very different barrier distributions contributed to the relaxation behavior. We have demonstrated experimentally that only energy barrier distributions and the thermal activation process could not account for a plateau in the viscosity data at low temperatures. Quantum tunneling of magnetization is suggested below ∼3 K. © 1996 The American Physical Society.