Electrical surface-resistivity, dielectric resonance, polarization and magnetic properties of Bi0.5Sr0.5FeO3−δ thin films grown by pulsed laser deposition

Abstract

Polycrystalline and highly preferred orientated Bi0.5Sr0.5FeO3−δ thin films were grown by pulsed laser deposition (PLD) on n-Si (2 0 0) and MgO (2 0 0) single crystalline substrates respectively. The thin films were inspected using x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy and atomic force microscopy techniques. The electrical surface-resistivity, dielectric resonance, electric polarization, and magnetic properties of the thin films were studied. At room temperature, depending on deposition conditions, the polycrystalline thin films grown on n-Si substrates were found to exhibit an electrical surface-resistivity of the order of 103–106 Ω, a piezoelectric resonance in the frequency range of about 25–26 MHz, a relaxor-type ferroelectric hysteresis with a maximum polarization of 0.015–0.055 µC cm−2 and magnetic hysteresis. Similarly, the thin films grown on MgO substrates exhibited an electrical surface-resistivity of the order of 109 Ω, multiple piezoelectric resonances in the frequency range of about 8–45 MHz, a linear variation of polarization with applied electric field and either a linearly varying magnetization or magnetic hysteresis which depends on the deposition conditions.