1. A resistance-switching memory cell, comprising: first and second electrodes; an intermediate material electrically between, and in series with, the first and second electrodes; a low current resistance-switching material electrically between, and in series with, the first electrode and the intermediate material; and a high current resistance-switching material electrically between, and in series with, the second electrode and the intermediate material, the low current resistance-switching material and high current resistance-switching material have respective bipolar switching characteristics, a reset switching current of the high current resistance-switching material is higher than a set and/or reset switching current of the low current resistance-switching material by a factor of at least 1.5.