Inverse single-sided magnet

Ishitobi, Takayuki

We propose the concept of an inverse single-sided magnet, which contrasts with conventional single-sided magnets that emit magnetic fields only on one side. Instead of being a ferromagnetic material, the inverse single-sided magnet selectively responds to only one type of magnetic pole-either north or south-while remaining inert to the opposite pole. We demonstrate this behavior in a model of a quantum octupolar magnet with collinear magnetic order and site-dependent anisotropy, showing that magnetization remains zero under a field in one direction and polarized in the opposite direction. Acting as a "magnetic diode," the inverse single-sided magnet holds promise for advanced applications in magnetic sensors, encoders, and actuators, and could enable new directions in both fundamental science and technology.