Patent ID: 7965586

Claim:
A magnetization detecting method, comprising: disposing a metal probe opposite to a recording medium having a magnetic recording layer in which information is recorded based on the direction of in-plane magnetization; irradiating a region of the recording medium opposite to the metal probe with incident light having its polarization state modulated; and detecting the direction of magnetization in the region of the recording medium opposite to the metal probe based on the change in tunnel current that flows between the metal probe and the surface of the recording medium or the change in polarization intensity of reflected light reflected by the metal probe and the surface of the recording medium; wherein linearly-polarized light having an oblique incident angle Φ with π/4 ≦Φ<π/2 and two symmetric angles of +θ and −θ with π/4 ≦θ<π/2 with respect to the direction perpendicular to the surface of the recording medium is alternately caused to be incident; and wherein a difference between squares of an electric field of the reflected light in a direction of the probe is measured.