Anomalous magnetic properties of Tb/Cr multilayer

We report the magnetic properties of [Tb/Cr]8 multilayer in which the Curie temperature(TC)of ferromagnetic Tb is much lower than the Néel temperature (TN) of antiferromagnetic Cr. An unexpected coercivity enhancement is observed at temperature above TN. Furthermore, the magnetic hysteresis loops measured after cooling in an applied field of 10kOe exhibit “double hysteresis loops” behaviors at 156–216K. The abnormal temperature dependence of coercivity is correlated with the spin-density wave structure of Cr, the competition between ferromagnetic and antiferromagnetic coupling at the interface of Tb and Cr layers as well as the interlayer coupling of the adjacent Tb layers.