the variable resistor is formed of a metal oxide showing an n type conductivity, and {HEAD ~ a work function} of {TAIL ~ the second electrode} is larger than a work function of the first electrode 
the variable resistor is formed of a metal oxide showing an n type conductivity , and { HEAD ~ a work function } of { TAIL ~ the second electrode } is larger than a work function of the first electrode
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH