Observing the Berry phase in diffusive conductors: Necessary conditions for adiabaticity

We investigate Berry phase effects in the magnetoconductance of diffusive s ystems, and determine the precise criterion for adiabaticity within the wea k-localization formalism. We show that the exact solution of the Cooperon p ropagator for the special case of a cylindrically symmetric texture agrees with the adiabatic approximation in the adiabatic limit characterized by ta u much greater than(1/d)(l(2)/L-2). We point out that orientational inhomog eneities in the magnetic field induce dephasing effects that can mask the B erry phase (and any other phase-coherent phenomena) for certain parameter v alues of system and field. [S0163-1829(99)09119-5].