"Unveiling the New Hall Effect: Expanding the Frontiers of Physics"
Scientists have discovered an anisotropic anomalous Hall effect in a spinel oxide thin film, which varies with current direction and is explained by a new model involving a magnetic toroidal quadrupole structure, aligning with Onsager’s theorem. This phenomenon contradicts Onsager’s reciprocal theorem and has not been observed before. The study proposes a physical model that successfully accounts for the coexistence of the magnetic toroidal quadrupole and ferromagnetism owing to conical magnetic anisotropy, pushing the boundaries of traditional physics.