Phase-change material and phase-change type memory device

A phase-change material, which has a high crystallization temperature and is superior in thermal stability of the amorphous phase, which has a composition of the general chemical formula GexMyTe100-x-y wherein M indicates one type of element which is selected from the group which comprises Al, Si, Cu, In, and Sn, x is 5.0 to 50.0 (at %) and y is 4.0 to 45.0 (at %) in range, and x and y are selected so that 40 (at %)≦x+y≦60 (at %). This phase-change material further contains, as an additional element L, at least one type of element L which is selected from the group which comprises N, O, Al, Si, P, Cu, In, and Sn in the form of GexMyLzTe100-x-y-z wherein z is selected so that 40 (at %)≦x+y+z≦60 (at %).