Invited (remote)
Room temperature nanoscale multiferroic thin films with large magnetoelectric coupling

Multiferroic materials with robust magnetoelectric coupling at room temperature are of current research interest for their multifunctional device applications. Highly (100) oriented Pb(Fe0.5Ta0.5)x(Zr0.53Ti0.47)1-xO3 (PZTFTx) multiferroic thin films were deposited on La0.67Sr0.33MnO3 (LSMO) coated MgO (100) substrates using pulsed laser deposition technique. The film thicknesses were around 300 nm. X-ray diffraction analysis suggested tetragonal symmetry in these films at room temperature. Dielectric measurements on metal-ferroelectric-metal thin film capacitors were carried out between 100-106 Hz that revealed a broad dielectric peak maximum temperature at around Tm ~520 and 560 K for x = 0.2 and 0.3 films respectively, suggesting diffuse ferroelectric to paraelectric phase transition. The polarization-electric field (P-E) loop in the films exhibited a high saturation polarization of ~ 71 µC/cm2 and a large coercive field of 4.5 kV/cm, revealing its ferroelectric behavior. The thin films showed saturation magnetization of 8.3 (x =0.2), and 6.1 (x = 0.3) emu/cm3 at room temperature and had retained ferromagnetic/ferrimagnetic ordering at room temperature. The maximum magnetoelectric coupling in x =0.2 and 0.3 thin films were found to be 18.76 V/cm.Oe and 17.41 V/cm Oe respectively for in-plane bias field of around 350 Oe at room temperature, which are perhaps the largest values reported for single crystalline thin films and hence suitable for spintronic device applications.