UHV-preparation and in situ characterization of magneto-optical thin films

Rare-earth transition metal films of thickness d approximately=100 nm have been prepared by ion-beam sputtering in ultrahigh vacuum. 99.99%-pure alloys, e.g. Tb₂₂Fe₇₈ or elements like Nd, Gd, Tb, and Fe or Co are used as target materials. Sputtering sources are either cold-cathode sources (1 mA/cm²) or focused two-grid hot-filament sources (10 mA/cm²) of the Kaufmann type, yielding sputtering rates of up to 5 AA/s. Film growth is controlled in situ by a magnetooptical technique that provides information on the reflectivity and the Kerr rotation angle as a function of film thickness. Directly after deposition the samples are transferred to an interconnected analysis chamber, where composition and cleanliness of films as well as targets are checked using X-ray photoemission spectroscopy.