Byusingsurfaceeffects（Augerelectronspectroscopy,X-rayphotoelectronspectroscopy,polarKerreffect）andvolumeeffects（magnetization,torquecurve）thephysicalprocessofsurfaceoxidationofrareearth-transitionmetalamorphousmagneto-opticalthinfilmswasstudiedinthispaper.Therareearthelementsoxidizepreferentiallyandrichatthefilmsurface,andthetransitionmetalsdepleteinoxidationlayer.Fe2O3inthesurfaceoxidationlayercontributestotheplanarmagnetization,andtherebytheanomalouspeakappearsnear180°onthetorquecurvesandtheamplitudeofthepeaksisrelatedtothedepthofsurfaceoxidationlayers.Theironbondstooxygeneasierthanthecobolt.RE-Comagneto-optiealthinfilmshavegoodpropertiesofresistancetooxidationandhumidity.
