"Phase change memory (PCM) is an emerging non-volatile memory
technology pioneered by Intel, Numonyx, Samsung and others.
"Last updated: Friday, March 12, 2010
"Abbreviated as PCM, phase change memory is a type of
non-volatile memory that is much faster than the common flash
memory, and it also uses up to one-half the power. It works by
using a semiconductor alloy that can be changed rapidly between an
ordered, crystalline phase having lower electrical resistance to a
disordered, amorphous phase with much higher electrical resistance.
Because no electrical power is required to maintain either phase of
the material, so phase-change memory is non-volatile."