High-Field Hall Effect and Crystal Orientation Dependence of Magnetoresistance in Thin Films of CeAl sub 3

Thin films of CeAl sub 3 on sapphire were prepared by metallic coevaporation and in vacuo annealing. Highly oriented growth with the hexagonal crystal basal plane parallel to the substrate plane was observed. The resistivity vs. temperature curves of the best films were similar to bulk CeAl sub 3 , including a T exp 2 dependence < 0.3K. Transverse magnetoresistivity and Hall effect were measured in fields to 23 T and at temperatures down to 70 mK. Transverse magnetoresistivity was highly dependent on magnetic field orientation with respect to the basal plane. With the field perpendicular to the basal plane, the low-field magnetoresistivity became positive < 5K, and the high-field magnetoresistivity exhibited a temperature-dependent maximum. With the field in the basal plane, the low-field magnetoresistivity remained negative down to 2K, below which it exhibited a temperature-independent maximum at 1.8 T. The high-field Hall coefficient < 5K decreased with field at a temperature-dependent manner, but was temperature-independent at all fields < 800 mK. Graphs. 8 ref.--AA