Conduction mechanism in epitaxial BiFe0.95Mn0.05O3 thin film
Résumé
An epitaxial BiFe0.95Mn0.05O3 thin film of about 280 nm thickness was deposited on conductive SrRuO3 on a (001) LaAlO3 substrate by pulsed laser deposition. At room temperature, x-ray diffraction and Raman spectroscopy evidenced a pure rhombohedral structure and the hysteresis loop measurements showed a remanent polarization of Pr = 73 mu C/cm(2). The transport mechanisms were investigated from 90 to 400K and compared to several models. It was found that the nearest neighbor hopping and variable range hopping mechanisms dominate the conduction above and below 270K, respectively. Bulk like limited transport is attributed to hopping from and within trap levels depending on the temperature. Defects (vacancies) and manganese multiple valences play a major role in the electronic transport of such a strongly correlated system and should be considered to explain the recently observed photovoltaic effect in similar heterostructures. Published by AIP Publishing.