Effect of (Cr, Fe)-substitution at B sites of CuB1-x(Cr1/2Fe1/2)xO2 delafossite oxides on optical, magnetic, and dielectric properties

Abstract

In this work, we report room temperature ferromagnetic and colossal dielectric behavior in delafossite oxides of CuB1-x(Cr1/2Fe1/2)xO2 with x = 0.01 and 0.03. All samples were synthesized by the solid-state reaction method. The microstructure, optical, magnetic, and dielectric properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-visible spectroscopy, vibrating sample magnetometer (VSM), and impedance analyzer, respectively. The crystal structure of all samples was found to be of the R-3m delafossite structure, while their particle size was ~ 300 nm in the undoped sample (x = 0) and slightly increased with increasing x value. Regarding their optical properties, we observed the absorbance peak at wavelength ~250 nm corresponding to the direct optical band gap of about 2.90, 2.88, and 2.85 eV for sample x = 0.00, 0.01, and 0.03, respectively. The magnetic properties of the doped samples (x = 0.01 and 0.03) exhibited a ferromagnetic behavior at room temperature with a finite coercivity of about ~300 Oe. Furthermore, the magnetization of this CuB1-x(Cr1/2Fe1/2)xO2 delafossite is increased with increasing x value. Finally, the dielectric measurements revealed that Cr plays a role in maintaining the dielectric permittivity of the CuB1-x(Cr1/2Fe1/2)xO2 samples.

Keywords

• delafossite oxides
• cubo2
• magnetic properties
• dielectric properties