Pulsed laser deposition and characterization of Bi 3.25Nd 0.75Ti 3O 12 thin films buffered with La 0.7Sr 0.3MnO 3 electrode

Abstract

Bi 3.25Nd 0.75Ti 3O 12 (BNT) ferroelectric thin films with a thickness of ∼0.5 μm, on substrates of Pt/Ti/SiO 2/Si, (100) SrTiO 3 and (100) MgO, with a 0.4-μm-thick La 0.7Sr 0.3MnO 3 (LSMO) layer as bottom electrode, were deposited via pulsed laser deposition. The multilayer thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical measurement. The LSMO layers on Pt/Ti/SiO 2/Si were polycrystalline, while those on SrTiO 3 and MgO single crystal substrates were highly c-oriented. The BNT films were polycrystalline on LSMO covered Pt/Ti/SiO 2/Si and MgO, and c-axis oriented on LSMO/SrTiO 3. Dielectric constant and loss tangent (at 1 kHz) of the BNT thin films on LSMO buffered Pt/Ti/SiO 2/Si, STO and MgO substrates were 224, 263 and 204, and 0.03, 0.04 and 0.05, respectively. They had a remnant polarization of 25.4, 29.5 and 19.1 μC/cm 2, and a coercive field of 133, 176, 134 kV/cm, respectively. No fatigue was found for all the three BNT thin films up to 3×10 10 switching cycles.