  The magnetoresistance (MR) of CeCoIn5 is notably different from that expected
for orbital MR due to the Lorentz force and described by Kohler's rule which
holds in many conventional metals. We show that a pronounced crossover from
negative to positive MR of CeCoIn5 that occurs at elevated temperatures is
determined by the dependence of the effective mass M*(B,T) on both magnetic
field B and temperature T. Thus, the crossover is regulated by the universal
behavior of M*(B,T) observed in heavy-fermion metals. This behavior is
exhibited by M*(B,T) when a strongly correlated electron system transits from
the Landau Fermi liquid behavior induced by the application of magnetic field
to the non-Fermi liquid behavior taking place at rising temperatures. Our
calculations of MR are in good agreement with facts and reveal new scaling
behavior of MR.
