Patent Number: 
Section: claims

1. A thermal-assisted magnetic recording disk comprising:a disk-like glass substrate; anda recording layer formed on a main surface of the glass substrate, the recording layer including a plurality of recording magnetization portions arranged in a concentric manner around a center of the glass substrate and a plurality of non-magnetization portions having a thermal conductivity lower than that of the recording magnetization portions, each of the non-magnetization portions being disposed between adjacent recording magnetization portions along a circumferential direction on the main surface of the glass substrate, whereina mean squared roughness of a first area of the main surface of the glass substrate where each of the non-magnetization portions is formed is equal to or smaller than 1 nanometer,a width of each of the non-magnetization portions is between 30 nanometers and 140 nanometers, anda thermal conductivity of each of the non-magnetization portions is equal to or lower than one hundredth of a thermal conductivity of each of the recording magnetization portions and in a range from 1×10−3 W/(m·K) to 1 W/(m·K). 2. The thermal-assisted magnetic recording disk according to claim 1, whereinan average roughness of each of a second area of the main surface of the glass substrate where each of the recording magnetization portions is formed and the first area is equal to or smaller than 1 nanometer, anda maximum roughness of each of the first area and the second area of the main surface is equal to or smaller than 15 nanometers. 3. The thermal-assisted magnetic recording disk according to claim 1, wherein a difference of temperature between each of the non-magnetization portions and each of the recording magnetization portions is equal to or higher than 150° C. when each of the recording magnetization portions are illuminated with a laser light. 4. The thermal-assisted magnetic recording disk according to claim 1, further comprising a protecting layer formed on the recording layer, wherein the protecting layer is formed with a dielectric material that is optically transparent with respect to a laser light. 5. The thermal-assisted magnetic recording disk according to claim 4, wherein the dielectric material is optically transparent with respect to the laser light having a wavelength of 400 nanometers.