MAGNETOTRANSPORT BEHAVIOR OF HEAVY FERMION THIN-FILMS

Heavy fermion compounds such as CeAl3, CeCu6, UBe13, and CePb3, show a crossover from negative to positive transverse magnetoresistance as temperature is lowered. We have prepared high quality thin films of these materials in order to investigate their magnetoresistance . For the noncubic systems CeAl3 and CeCu6, positive magnetoresistance occurs only for certain field orientations relative to the crystal axes. For CeAl3 and CePb3, a temperature-dependent resistivity maximum occurs at fields H(m)(T), above which d-rho-/dH is negative for all field orientations. The maxima obey the relation [GRAPHICS] where T(x) is the crossover temperature from negative to positive initial magnetorestivity. Scaling of the magnetoresistance as a function of H/T is observed in separate high- and low-temperature regimes. A two-band model can be invoked to explain these and other experimental data.