Structural, vibrational, electrical and optical properties on Cr-doped LaAlO₃

The oxides with perovskite-type structure have been largely studied in last decades. This classes of materials show a large variety of properties such as ferroelectricity, superconductor, multiferroic, transparent conductor oxides among other properties. The perovskite compound LaAlO₃ has been used as a substrate in many applications. The high dielectric constant observed in this compound is ideal to reduce the loss of energy in devices working at high frequency. In this work, we will report the structural, vibrational, electric and optical of Cr-doped LaAlO₃ ceramics produced by combustion method. We observe a structural phase transition from rhombohedral to an orthorhombic structure with the increase of the Cr amount. It was possible to observe a reduction of the optical bandgap as well as a reduction of the resistivity of the compound. The Raman spectrum as a function of temperature reveals the nature of the structural transition in this compound. The change of the Cr amount can be used to produce new color pigments range from orange/yellow to green/blue.