SPINTRONICS An alternating alternative

Park and co-authors undertook a research to demonstrate the antiferromagnetic tunneling anisotropic magnetoresistance phenomena. The team reported on a large magnetoresistive effect at relatively small magnetic fields induced by an antiferromagnetic component in a magnetic multilayer device. The resistance of the device to an electric current perpendicular to the layers is determined by the angle between the magnetization directions of the ferromagnetic layers. Park placed a ferromagnetic layer (NiFe) on top of the antiferromagnetic one, which allows manipulation of the moments within the antiferromagnet through exchange coupling. All magnetic moments in the antiferromagnetic layer are rotated and wind up, forming a so-called exchange spring. Park measured a large (∼160%) change in resistance of the device, in response to a relatively small (∼50 mT) externally applied magnetic field. Park showed the direct influence of an antiferromagnet on the electric current in a layered material.