Potential and Impedance Imaging of Polycrystalline BiFeO₃ Ceramics

Abstract

Electrostatic-force-sensitive scanning probe microscopy (SPM) is used to investigate grain boundary behavior in polycrystalline BiFeO 3 ceramics. Scanning surface potential microscopy (SSPM) of a laterally biased sample exhibits potential drops due to resistive barriers at the grain boundaries. In this technique, the tips acts as a moving voltage probe detecting local variations of potential associated with the ohmic losses within the grains and at the grain boundaries. An approach for the quantification of grain boundary, grain interior, and contact resistivity from SSPM data is developed. Scanning impedance microscopy (SIM) is used to visualize capacitive barriers at the grain boundaries. In SIM, a dc-biased tip detects the variations of local potential induced by the lateral ac voltage applied to the sample. Unlike the traditional dc and ac transport measurement, both of these techniques are sensitive to the variation of local potential (SSPM) or local voltage oscillation amplitude and phase (SIM), rather than to current. Therefore, special attention is paid to the relationship between SSPM and SIM images and data obtained from traditional impedance spectroscopy and dc transport measurements. For BiFeO 3 ceramics excellent agreement between the local SIM measurements and impedance spectroscopy data are demonstrated.

Dielectric and magnetic properties of Ba-, La- and Pb-doped Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3 perovskite ceramics

“…22 All these phenomena often make it difficult to detect the FE-PE transition by electrical investigations. The diffuse character of the phase transition can be understood in terms of the inhomogeneous composition both in A and B sites of the ABO 3 perovskite cell. "…”

Application of dynamic impedance spectroscopy to atomic force microscopy

“…Important scientific possibilities offered by the above-mentioned techniques prompted worldwide effort to combine them. Fundamental research in this field was documented by Kalinin et al [19][20][21] and O'Hayre et al [22,23]. Two distinct techniques were proposed, namely, impedance imaging and spectroscopy.…”

Hydrothermal Synthesis of BiFeO₃ Fine Particles

“…and Chen et al adopted short time (6h.). When iron oxides are prepared in FeSO 4 or FeCl 2 solution, in low pH solution iron oxyhyroxides are precipitated and in higher pH solution iron oxides can be crystallized 14) . In this work an oxyhyroxide or oxynitrate including bismuth and iron atoms may be crystallized in lower concentration of KOH solution and BFO can be prepared by increasing concentration of KOH.…”

“…BFO has been studied extensively for preparation and multiferroic properties [3][4] . In 2007 it was reported that BFO had photocatalytic activity under visible light irradiation 5) .…”