| 摘要 |
A device for the direct visualization of flaws in a material. A magnetic garnet epitaxial film (20, 21) is deposited on either side of a non-magnetic substrate (10). A reflective material (22) is provided adjacent to the epitaxial film (20,21) and the substrate (10) with its associated layers is placed over a sheet of current carrying material (26) and is placed over the material (25). A bias magnetic field is then applied to the substrate together with its epitaxial film. Polarized light (33) is transmitted onto the substrate (10) and is reflected through the epitaxial layer (20, 21) and back out of the substrate (10). The existing magnetization interacts with magnetic fields associated with eddy currents flowing adjacent to flaws in the material, such that the domain structure of the epitaxial film is altered. The altered domain structure induces a rotation of the plane of polarization of the incident projected light. When viewed through a polarizing material, the rotation of the reflected light renders the flaws directly visible. |
