An electrically operated, overwritable, multivalued, non-volatile resistive
memory element is disclosed. The memory element includes a two terminal
non-volatile memory device in which a memory film material is included,
and a circuit topological configuration is defined. The memory device
relates generally to a unique new electrically induced variable resistance
effect, which has been discovered in thin films of colossal
magnetoresistive (CMR) oxide materials. The memory material is
characterized by: 1) the electrical control of resistance through the
application of short duration low voltage electrical pulses at room
temperature and with no applied magnetic field; 2) increase of the
resistance or decrease of the resistance depending on the polarity of the
applied pulses; 3) a large dynamic range of electrical resistance values;
and 4) the ability to be set at one of a plurality of resistance values
within said dynamic range in response to selected electrical input signals
so as to provide said single cell with multibit/multivalued storage
capabilities. The memory element includes a circuit topology to construct
a ROM/RAM configuration. The features of the memory element circuit are:
1) the ability to set and then measure the resistance of the two terminal
multi-valued memory devices with negligible effects of sampling voltage
and current; and 2) the ability to step up or down the resistance value,
i. e., to set one of multiple number of resistance states, with repeated
applications of pulses of varying amplitude.