Photoconductivity and photo-detection response of multiferroic bismuth iron oxide

We report visible light detection with in-plane BiFeO3 (BFO) thin films grown on pre-patterned inter-digital electrodes. In-plane configured BFO film displayed photocurrents with a 40:1 photo-to-dark-current ratio and improved photo-sensing ability for >15000 s (4 hrs) under small bias voltage (42V). Nearly sixty percent of the photo-induced charge carriers decay in 1.0 s and follow a double-exponential decay model. At 373 K the effect of light does not significantly increase the dark current, probably due to reduced mobility. Sub-bandgap weak monochromatic light (1 mw/cm2) shows one fold increase in photo-charge carriers.Comment: 18 pages, 7 figure

Magnetodielectric coupling in epitaxial Nd2CoMnO6 thin films with double perovskite structure

Double perovskite Nd2CoMnO6 thin films have been grown epitaxially on SrTiO3 substrates using pulsed laser deposition and their structural, magnetic, and dielectric properties were investigated. Temperature dependent dielectric (epsilon) constant is measured in the frequency range between 1 kHz and 1MHz under applied magnetic fields up to 0.5 kOe. The dielectric constant exhibits an anomaly near to the Curie temperature which is independent of magnetic field and can be corroborated with a loop opening temperature in zero-field-cooled and field-cooled magnetization measurements. While, a linear relationship between magnetodielectric constant, delta epsilon(MD), and M-2(magnetization) in the paramagnetic to ferromagnetic regime proves magnetodielectric coupling between ferroelectric and ferromagnetic orders in this single-phase perovskite system

Probing luminescent Fe-doped ZnO nanowires for high-performance oxygen gas sensing application

Herein, we demonstrate the growth of Fe-doped ZnO nanowires using a typical vapour phase transport process for oxygen gas sensing application. The morphologies of these nanowires have been evaluated by high-resolution transmission electron microscopy, which confirms the formation of ZnO nanowires with 20-50 nm diameter and with a d-spacing of similar to 0.270 nm, corresponding to (002) planes. The energy dispersive X-ray spectroscopy result reveals the presence of Fe, Zn and O elements in 9 wt% Fe-doped ZnO nanowires. The Raman and photoluminescence spectroscopy results explore the oxygen deficient structure of these nanowires with Fe ion occupying tetrahedral sites in the ZnO lattice along with some interstitial Zn and Fe ions. Furthermore, these nanowires arrays illustrate a sensitivity of 23 and 31 with fast response/recovery times of about 38 s/46 s and 11 s/11 s at an operating temperatures of 100 degrees C and 140 degrees C, respectively. The obtained results established that these luminescent ZnO nanowires could be an excellent choice for high-performance oxygen gas sensing application