Information recording medium and information recording device

Abstract

An information recording medium capable of high-density recording and accurate reproduction and also capable of repeated recording and reproduction, an information recording device that employs the information recording medium has a Co—Si oxide thin filmconstructed such that columnar crystalsare separated by an intergranular phasewhich contains SiOhaving a lower coefficient of thermal conductivity than the columnar crystals. Therefore, the intergranular phaseprevents heat transfer from one columnar crystalto another. In addition, the intergranular phaseseparates columnar crystalsfrom each other, so that the crystalline structure of each columnar crystalis not affected by its adjacent columnar crystal. The advantage of such construction is that the columnar crystalsdo not undergo phase transformation except for those which were given energy necessary for phase transformation directly from the laser beam, and hence columnar crystalsoverheated by the laser beam do not affect their adjacent columnar crystals. Thus it is possible to accurately form recording pits whose mark length is smaller than the laser beam diameter.