Optical studies of multiferroic HoCrO3 perovskite compound for optoelectronic device applications

Abstract The multiferroic HoCrO3 orthochromite compound was prepared using the sol-gel method. The optical properties of this ceramic were characterized by infrared (IR) and UV–Vis absorption spectroscopy. The IR spectrum shows a set of absorption peaks that can be assigned to the Cr–O and O–Cr–O vibrations. From UV–Vis absorption spectrometry, the reflectance spectrum and the Tauc model, reveal a direct and wide optical band gap evaluated at 3.34 eV and 3.206 eV respectively. The high value of the Urbach energy (528 ± 13) meV shows the presence of a high density of localized states. The extinction coefficient (k) was used to estimate the evolution of the refractive index n with the wavelength. Additionally, n obeys to Cauchy relation. Furthermore, the dispersion parameters were analyzed in the bases of Wemple and Di-Domenico model. The optical constants such as the skin depth and the optical conductivity were calculated and the results are discussed. From the UV–vis absorbance spectrum attributed to the d-d transitions of Cr3+ ion in HoCrO3, a theoretical crystal-field analysis is realized which leads to a good agreement between the calculated and the experimental energy levels. Furthermore, the electronic structure was compared with that obtained for Cr3+ ion in PrCrO3 ceramics. From Racah theoretical study, Tanabe Sugano Diagram and Photoluminescence measures, a transfer charge mechanism is proposed. The achieved results confirm the importance of our compound in optoelectronic device applications.