Type of Magnetic Field Dependency of AC Susceptibility of Rare Earth Titanates

Resumo

The nanocomposite artificial crystals with embedded magnetic nanoparticles are obtained from opal matrices composed of the submicron SiO₂ spheres. The introduced particles are sized from 5 to 60 nm. These artificial crystals contain particles of several rare earth titanates with pyrochlore structure. Low temperature magnetic properties of these nanocomposite materials have been investigated. The frequency and magnetic field dependences of AC magnetic susceptibility of nanocomposites with Gd₂Ti₂O₇, Dy₂Ti₂O₇, Sm₂Ti₂O₇, Nd₂Ti₂O₇ and Er₂Ti₂O₇ particles have been measured in temperature range from 2 to 10 K at frequencies from 1 Hz to 10 kHz. It has been established that magnetic field dependences of these rare earth nanocomposite titanates obey Cole-Cole-like formula written for magnetic field dependency of AC magnetic susceptibility.