JPS6457441A - Magneto-optical disk - Google Patents

Abstract

PURPOSE:To prevent the cracking of a recording layer and protective layer and the generation of layer exfoliation by forming a stress balance layer satisfying specific conditions on the surface of the side opposite to the surface formed with the recording layer. CONSTITUTION:The stress balance layer 5 consisting of the acid nitride of silicon is formed on the surface of a resin substrate 1 on the side opposite to the surface formed with the recording layer (the outside surface of the substrate). The internal stress sigmab of the stress balance layer 5 is so set as to have a difference of a prescribed value or below from the internal stress sigmat over the entire part of an information forming layer 7, i.e., the equation ¦(sigmat-sigmab)/(sigmat+sigmab)¦<0.1. Then, the balance of the stress is maintained between the information forming layer 7 and the stress balance layer 5 even if the stress in the plane direction of the substrate at the boundary face between the substrate 1 and the thin layers is increased by a change in the ambient environmental temp. The possibility of generating the crack and layer exfoliation in the respective thin layers to constitute the information forming layer is thereby decreased and the degradation in the quality of the recording medium is prevented.