  We report on Cr doping effect in Mn3Sn polycrystalline films with both
uniform and modulation doping. It is found that Cr doping with low
concentration does not cause notable changes to the structural and magnetic
properties of Mn3Sn, but it significantly enhances the anomalous Hall
conductivity, particularly for modulation-doped samples at low temperature. A
Hall conductivity as high as 184.8 {\Omega}-1 cm-1 is obtained for
modulation-doped samples at 50 K, in a sharp contrast to vanishingly small
values for undoped samples at the same temperature. We attribute the
enhancement to the change of Fermi level induced by Cr doping
