of 20 atomic and hence it is necessary to set the content a of sb to be less than 80 atomic further if the content c of te is increased the crystallization speed is lowered however when attention is paid to the ratio between the content b of mn and the content c of te if the content b of mn and the content c of te is approximately 1 1 that is if the composition ratio b c between mn and te is set to be in the vicinity of 50 50 it is possible to increase the crystallization speed for this reason it is preferred that the content c of te is increased with an increase in the content b of mn or decreased with a decrease in the same more specifically the composition of the recording layer is further expressed from a viewpoint different from that of the above formula 1 by the following formula 2 wherein when d and e are expressed in terms of atomic in the above formula 2 the composition ratio between mn and te is set to satisfy the following conditions this configuration makes it possible to simultaneously attain a further increased crystallization speed or increased rewriting speed and excellent thermal stability for example it is possible to increase the rewriting speed up to a range of approximately 100 mbps to approximately 200 mbps while maintaining the crystallization temperature above 200 u00b0 c thus a recording layer can be realized which enables high speed rewriting and at the same time has excellent storage characteristics further the recording layer can contain not only the above elements but also other elements added thereto.