Nonvolatile memory elements are provided that have resistive switching metal oxides. The nonvolatile memory elements may be formed from resistive-switching metal oxide layers. Metal oxide layers may be formed using sputter deposition at relatively low sputtering powers, relatively low duty cycles, and relatively high sputtering gas pressures. Dopants may be incorporated into a base oxide layer at an atomic concentration that is less than the solubility limit of the dopant in the base oxide. At least one oxidation state of the metal in the base oxide is preferably different than at least one oxidation sate of the dopant. The ionic radius of the dopant and the ionic radius of the metal may be selected to be close to each other. Annealing and oxidation operations may be performed on the resistive switching metal oxides. Bistable metal oxides with relatively large resistivities and large high-state-to-low state resistivity ratios may be produced.