TEMPERATURE-DEPENDENT SURFACE MAGNETIZATION OF FENI3(111) STUDIED BY SPIN-RESOLVED APPEARANCE-POTENTIAL SPECTROSCOPY

The temperature-dependent magnetic properties of the: FeNi3(lll) surfa ce were investigated by means of spin-resolved appearance potential sp ectroscopy. Within the: temp erature range studied, from LOO K to 1100 K, two phase transitions occur in the built: a compositional: order-d isorder phase transition between 770 and 785 K and a ferromagnetic-par amagnetic phase transition with a Curie temperature of 863 K. The firs t one does not show up in the appearance potential signals of Fe and N i, while the latter is reflected in the spin-asymmetry signals; Both t he Fe and the Ni signals follow the bulk magnetization curve of FeNi3 with no evidence of any exceptional surface magnetic properties. Furth ermore our data show that; to a good approximation, the spin asymmetry of the appearance potential signal is proportional to the magnetizati on.