We report a resistive probe that detects electric field by field-induced resistance changes in a small resistive region at the apex of the tip and demonstrate a method of imaging ferroelectric domains at high speed, which is named scanning resistive probe microscopy (SRPM). We designed and fabricated the probe by self-aligning process that readily implemented the resistive region at the tip apex. In order to measure the field sensitivity, we contacted the probe with a thermally oxidized silicon sample and detected a 0.3% resistance change per volt applied to the sample. We obtained domain images of freshly cleaved triglycine sulfate (TGS) single crystal by contact mode SRPM. The operating voltage of the probe was 4 V and the scan rate and size were 2 Hz and 40×40 μm2, respectively. We controlled the polarization of Pb(Zr0.4Ti0.6)O3 (PZT) by applying voltage between the resistive tip and the bottom electrode of PZT, and acquired the domain images with the same tip at 2 Hz scan rate. By controlling and detecting the ferroelectric domains without an additional signal modulating system, we verified that the resistive probe could detect the ferroelectric domain at high speed and be used as a read/write head of a probe data storage system.

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Nanoscale manipulation of surface charges and their imaging are essential for understanding local electronic behaviors of polar materials and advanced electronic devices. Electrostatic force microscopy and Kelvin probe force microscopy have been extensively used to probe and image local surface charges responsible for electrodynamics and transport phenomena. However, they rely on the weak electric force modulation of cantilever that limits both spatial and temporal resolutions. Here we present a field effect transistor embedded probe that can directly image surface charges on a length scale of 25 nm and a time scale of less than 125 μs. On the basis of the calculation of net surface charges in a 25 nm diameter ferroelectric domain, we could estimate the charge density resolution to be as low as 0.08 μC/cm(2), which is equivalent to 1/20 electron per nanometer square at room temperature.

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We report an intriguing magnetodielectric coupling in BaTiO 3 / ␥-Fe 2 O 3 dielectric core/ ferrimagnetic shell nanoparticles. The dielectric constant steeply increases with magnetic field, and the frequency dependent magnetodielectric curve shows a resonancelike peak at high temperatures, while it decreases smoothly with field and no peak appears in the frequency dependent magnetodielectric curve at low temperatures. We attribute the observed magnetodielectric coupling to the Maxwell-Wagner effect combined with magnetoresistance at high temperatures and to possible spin-lattice coupling and its modification near interfaces at low temperatures.

The structural, dielectric, magnetic, and magnetodielectric properties were systematically investigated for (1−x)BaTiO3−(x)LaMnO3 composites in wide temperatures, frequencies, and mole percent (x). Dielectric anomaly around 410 K and magnetic hysteresis at 293 K were clearly observed, which might imply the coexistence of ferroelectricity and ferromagnetism at room temperature. The values of magnetodielectric effect were well scaled with M2, i.e., ([ε(H)−ε(0)]/ε(0))∼M2, and were increased with x. The observed magnetodielectric effect were discussed in conjunction with the formation of a magnetoresistive (La,Ba)MnO3 phase.