Experimental and Computational Exploration of the Dilute Magnetic Delafossite CuAl1-xFexO2 Alloys

Abstract

Experimental and Computational Exploration of the Dilute Magnetic DelafossiteCuAl1-xFexO2 Alloys Mina AzizihaCuAlO2 is among several ternary delafossites, which is a rare p-type semiconductor with potential applications as a transparent conductive oxide, photocatalyst, and spintronics when doped with transition metal ions. Reported in this thesis are results from our investigations of CuAl1-xFexO2 (x = 0 to1) with a focus on the x-dependence of structural, magnetic, vibrational, optical properties, and the role of defects and impurities. Samples are prepared by solid-state reactions.We performed a complete study of magnetic properties to investigate the possibility of room temperature ferromagnetic alloys, which are used in transparent ferromagnet applications, suggested by a computational study. Analysis of magnetization (M) vs. temperature (T, from 2 to 300 K) data by Curie-Weiss law confirms Fe 3+ as the electronic state of Fe; this analysis also yields a negative θ characteristic of an antiferromagnetic Fe 3+ -Fe 3+ exchange coupling and magnitudes of x in good agreement with the nominal values. The isothermal M vs. H (up to H= 90 kOe) data analyzed by the modified Brillouin function support the results obtained from the M vs. T analysis. High-resolution M-H loop measurements at 300 K and 10 K show negligible coercivity (HC) at 10 K but HC ~ 100 Oe at 300K. The results suggest that the room temperature ferromagnetism can originate from hematite impurity, but not for CuAl1-xFexO2 alloys.