  The memristor is the fundamental non-linear circuit element, with uses in
computing and computer memory. ReRAM (Resistive Random Access Memory) is a
resistive switching memory proposed as a non-volatile memory. In this review we
shall summarise the state of the art for these closely-related fields,
concentrating on titanium dioxide, the well-utilised and archetypal material
for both. We shall cover material properties, switching mechanisms and models
to demonstrate what ReRAM and memristor scientists can learn from each other
and examine the outlook for these technologies.
