1. A memory structure, comprising: a memory cell having programmable material between a pair of electrodes; the programmable material comprising a multivalent metal oxide directly against a high-k dielectric; and a diode over the memory cell; the diode comprising a first diode electrode directly over one of the memory cell electrodes and electrically coupled with said one of the memory cell electrodes; the diode further comprising a second diode electrode laterally outward of the first diode electrode and not being directly over the memory cell.