Enhancement of multiferrocity in CuCrO2 compounds through effective doping induced optimization of localized carrier holes and reduction in helical disorder

Abstract

The bulk pristine CuCrO₂, doped CuCr_0.96M_0.03V_0.01O₂ (M = Ti, Mn, Ga and Nb), CuCr_0.96V_0.04O₂, CuCr_0.97Mg_0.03O₂, CuCr_0.97Ni_0.03O₂, and CuCr_1-xFe_xO₂ (x = 0.03, 0.06, and 0.09) compounds with single rhombohedral phase were investigated through low-temperature dc resistivity, field-dependent magnetization, and dielectric measurements. The room-temperature UV measurements were also carried out to determine possible changes in the optical bandgap due to the dopants mentioned above. The present work provides significant evidence of novel methodology for optimizing the number of localized carrier holes along with a reduction in helical disorder around MO₆ octahedra, which leads to enhancement of the double exchange along the Cr-O-M-O linkages or superexchange between M^3+/4+-Cr³⁺ mediated via oxygen. The nonmagnetic substitution in magnetic sublattice disrupts the spin spiral and a net weak component is realized in magnetization measurements.