Electrical and Optical Study of Multiferroic Superlattices

Highly oriented superlattices (SL) of ferroelectric (piezoelectric) PbZr$_{0.52}$Ti$_{0.48}$O$_{3}$ (PZT) and ferromagnetic La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ (LSMO) materials were grown on LaAlO$_{3}$ (100) substrates by pulsed laser deposition technique. The x-ray diffraction patterns of PZT/LSMO superlattices with different periodicity evidenced satellite peaks suggest the formation of SL without any secondary parasite phases. Surface topography showed well defined grain with surface roughness $\sim $2-5nm. Grain size and surface roughness changes with change of periodicity. Room temperature magnetization-field (M-H) exhibit well-shaped magnetization hysteresis loops good saturation and low coercivity. The structural, electrical and magnetic properties were studied. Polarized Raman Spectra showed soft transverse and longitudinal modes at 123 cm$^{-1}$ which soften near the ferroelectric phase transition of SLs. The electrical studies were conducted to understand the frequency and temperature dependent dielectric anomalies around to metal-ferromagnetic to insulator-paramagnetic transition temperature of LSMO.