STRUCTURE AND MAGNETIC-PROPERTIES OF FE EUO GRANULAR FILMS/

We produced Fe/EuO granular films by reactive co-evaporation, and meas ured their structural and magnetic properties using X-ray diffraction (XRD), transmission electron microscopy, and a superconducting quantum interference device magnetometer. The XRD patterns of Fe/EuO films de posited al substrate temperatures up to 200 degrees C show only weak p eaks due to Fe. while films deposited al 400 degrees C show diffractio n peaks due to Fe and EuO, indicating that all Fe/EuO granular film wa s formed. Magnetic measurements of the Fe/EuO granular films revealed the following: (i) the magnetization at 300 K shows typical ferromagne tic behavior, while that measured at 5 K shows non-saturating behavior with the magnetization above 15 kOe exceeding the saturation value at 300 K; (ii) the magnetization at a magnetic field of 10 kOe increases gradually with increasing temperature up to about 200 K, followed by a constant value, while that at 50 kOe shows an initial large value, w hich decreases to the constant value at around 200 K. These results in dicate that the coupling between the magnetic moments of Fe and those of EuO is non-collinear, and that the moments gradually align themselv es with an externally applied magnetic field.