Agirxg Changes of Some JPr-o^er-ties

The effectof Al additionon the deteriorationof TbFeAlfilms is discussed. Oxidationof films with no protective layerwas observedat temperatures between100° and 200°C.Variationin the transmittancewas attributedto thevaryingthicknessof the oxidationlayer.No pinholes were observed.The additionof Al to TbFe film reducesroom temperature oxidationbya factor of IO7.