Low-temperature magnetoresistance measurements of YbBe13

The temperature dependence of the resistance R( T) of YbBe13 is strongly in fluenced by a magnetic field. The maximum in R(T) at 2 K vanishes at fields above 2T whereas the maximum at 22 K broadens and shifts with increasing f ield to about 60 K at 20 T. The kink observed in R(T) as well as in the mag netoresistance R(B) corresponding to the AF transition allowed us to determ ine a magnetic phase diagram of YbBe13 showing a mean-field behaviour with B-c similar or equal to 0.67 T and T-N similar or equal to 1.05 K. TO expla in our results the Kondo scattering modified by crystal-field effects is su ggested. (C) 1999 Elsevier Science B.V. All rights reserved.