A data retention structure in a memory element that stores data as a plurality of conductivity profiles is disclosed. The memory element can be used in a variety of electrical systems and includes a conductive oxide layer, an ion impeding layer, and an electrolytic tunnel barrier layer. A write voltage applied across the memory element causes a portion of the mobile ions to move from the conductive oxide layer, through the ion impeding layer, and into the electrolytic tunnel barrier layer thereby changing a conductivity of the memory element, or the write voltage causes a quantity of the mobile ions to move from the electrolytic tunnel barrier layer, through the ion impeding layer, and back into the conductive oxide layer. The ion impeding layer is operative to substantially stop mobile ion movement when a voltage that is less than the write voltage is applied across the memory element.