Intrinsic magnetic order and inhomogeneous transport in Gd-implanted zinc oxide

We report the results from magnetic, resistivity, and Hall effect measurements on a ferromagnetically ordered 5% Gd low energy implanted ZnO single crystal. Temperature-dependent magnetization measurements show that the Gd ions do not contribute to the magnetic order; hence, the magnetic order is intrinsic. The electronic transport in the Gd-implanted region is inhomogeneous, and there is a nonlinear Hall resistance. The nonlinear Hall resistance is likely to be a consequence of the inhomogeneous transport and not due to an anomalous Hall effect.