Abstract:

Granular CoxC1-x and (Co/Pt)xC1-x thin films with different metal-volume fractions x are prepared by simultanious electron beam evaporation of Co or CoPt and C targets. The films are condensed on NaCl- and quartz substrates. The structure of the films is controlled by choosing different substrate temperatures Ts in the range between 20°C and 350°C as well as by annealing the thin film samples after generation at temperatures Ta between 200°C and 700°C. The structural properties of the films are examined by means of transmission electron microscopy and electron diffraction. Electrical resistivity of the films is measured in the temperature range between T = 4.2K and T = 300K. In order to reveal the magnetic properties of the granular thin films a SQUID magnetometer is used. In addition to the measurement of hysteresis loops at T = 4.2K and T = 300K, remanent magnetisation curves are measured in order to examine the magnetic coupling between the particles of the granular films. Additionally magnetoresistance measurements are performed at T = 4.2K.