Magnetodielectric properties of nanodisc bismuth ferrite grown within Na-4 mica nanochannels

Abstract

Bismuth Ferrite nanodiscs of ~0.6 nm thickness and 4.5 nm diameter have been synthesized within Na-4 mica nanochannels. The nanocomposite shows weakly ferromagnetic behavior. The zero field cooled magnetization data indicate a spin glass like behavior by the nanodisc surfaces with a freezing temperature of 10 K. The material shows superparamagnetic and strongly ferroelectric behavior at room temperature. A magnetodielectric coupling has been observed. The change in dielectric constant as a function of magnetic field up to 1.2 T is found to be ~12% at room temperature, which is much higher than that reported so far in the case of bulk bismuth ferrite systems. The dielectric response of this nanocomposite system has been studied in very high frequency range between 80 and 120 GHz at room temperature. The data indicate the presence of resonance interaction.