Magnetism and Magnetoelectricity of Textured Polycrystalline Bulk Cr₂O₃ Sintered in Conditions Far out of Equilibrium

Magnetoelectric antiferromagnets like Cr2O3 are attractive for the realization of energy-efficient and high-speed spin–orbitronic-based memory devices. Here, we demonstrate that the fabrication of polycrystalline bulk Cr2O3 samples in conditions far out of equilibrium relying on spark plasma sintering allows high-quality material with a density close to that of a single crystal to be realized. The sintered sample possesses a preferential [0001] texture at the surface, which can be attributed to uniaxial strain applied to the sample during the sintering process. The antiferromagnetic state of the sample and linear magnetoelectric effect are accessed all-electrically relying on the spin Hall magnetoresistance effect in the Pt electrode interfaced with Cr2O3. In line with the integral magnetometry measurements, the magnetotransport characterization reveals that the sample possesses the magnetic phase transition temperature of about 308 K, which is the same as in a single crystal. The antiferromagnetic domain pattern consists of small domains with sizes in the range of only several micrometers, which is formed due to the granular structure of the sample. The possibility to access the magnetoelectric properties of the samples relying on magnetotransport measurements indicates the potential of the polycrystalline Cr2O3 samples for prospective research in antiferromagnetic spintronics.