All-optical helicity dependent magnetic switching in an artificial zero moment magnet

Low remanent magnetization as key prerequisite for the ability of helicity dependent all-optical magnetic switching (AOS) is demonstrated for an artificial zero moment magnet. A heterostructure consisting of two amorphous ferrimagnetic Tb36Fe64 and Tb19Fe81 alloy layers is designed to yield a zero remanent net magnetization at room temperature by means of an antiparallel interfacial exchange coupling of the dominant magnetic moments. The canceling layer magnetizations provide vanishing demagnetization fields and the ability of AOS. Contrary to this, no all-optical switching is observed for single Tb36Fe64 and Tb19Fe81 films. This study provides further evidence that the ability for all-optical magnetic switching is correlated to the remanent sample magnetization and thus to the difference in magnetic moment of the rare-earth and transition-metal sublattices. (C) 2014 AIP Publishing LLC.