Structure-dependent spin-polarized electron transport in twin-crystal Cu1−xEuxO semiconductors

Abstract

In this work, Eu-doped twin copper oxide (twin Cu_1−xEu_xO) was synthesized using the gas–liquid phase chemical deposition method in combination with high-temperature oxidation. The incorporation of Eu³⁺ ions was affected by their diffusivity and the related charge trapping mechanisms. The twin Cu_1−xEu_xO configuration exhibited significant room-temperature ferromagnetism. From our analysis, it was demonstrated that as the Eu³⁺ doping concentration increased, the saturation magnetization first increased and then gradually decreased, reaching a peak at 0.82 at%. A p-type to an n-type semiconducting transition was also recorded as the doping concentration increased. A significant anomalous Hall effect characterized by a maximum anomalous Hall coefficient of 1.65, and a maximum Hall conductivity mobility of 16.50 Ohm⁻¹ cm⁻¹ and 250.59 cm² v⁻¹ s⁻¹, respectively, were derived for the twin Cu_1−xEu_xO, doped with 0.82 at% at room temperature. First-principles computational simulations were also conducted to elucidate the underlying mechanisms of the magnetic properties, the p-type to n-type transition, and the interplay between the spin-polarized states associated with 4f and carriers. In twin Cu_1−xEu_xO, the anomalous Hall effect originated from the contribution of the edge-to-jump scattering mechanism. The latter can be significantly enhanced by doping with Eu atoms, which yields the manifestation of the oblique scattering mechanism. Our work paves the way for the development of twin Cu_1−xEu_xO material structures, which emerge as an ideal candidate for future spintronic applications.