Various embodiments include a rotor having a dovetail slot with a bulbous fillet region, and in some cases, recessed inclined bearing surfaces. The shield layers have a distance therebetween shorter at a position where the electrode layer and magnetic domain control layer are laminated than that at a position where the magnetoresistive film is located. A second grating is formed having lines and spaces on the wafer using a second mask having a pattern for the second grating and also the pattern for forming the first grating. to accomodate electronic circuitry, or it is chamed as a reference pressure chamber of a relative pressure sensor.