[formula omitted]: A new paradigm for spin valves

A spin valve is a device structure whose electrical resistance can be manipulated by controlling the relative spin alignment of adjacent metallic, magnetic layers separated by nonmagnetic insulating layers. The spin valve effect is thought to be a delicate quantum phenomenon that depends upon the precision deposition and nanoscale patterning of artificial thin-film heterostructures whose quality and performance are difficult to control. We have observed a novel, strong spin valve effect in bulk single crystals of [formula omitted] having an anisotropic, bilayered crystal structure. This discovery opens new avenues for understanding the underlying physics of the spin valve effect, and for realizing their potential in practical devices.