Patent ID: 6927571

Claim:
An apparatus for examining magnetic properties of objects such as sheet material, including bank notes ( 20 ), comprising a magneto-optic layer having optical properties influenceable by the magnetic properties of an object to be examined, a light source arranged to produce light that is coupled into the magneto-optic layer, and a detector arranged to detect light that is transmitted and/or reflected by the magneto-optic layer, wherein the magneto-optic layer comprises iron garnets, whereby iron garnets are formed by compounds based on iron garnet (RE 3 Fe 5 O 12 ), where RE 3 comprises three rare earth metal elements, and wherein iron (Fe) and/or oxygen (O) can be substituted at least partly by one or more other elements in each case, the magneto-optic layer is applied to a substrate comprises gallium garnets, wherein gallium garnets are formed by compounds based on gallium garnet (RE 3 Ga 5 O 12 ), where RE 3 comprises three rare earth metal elements, and gallium (Ga) and/or oxygen (O) can be substituted at least partly by one or more other elements in each case, and wherein oxygen (O) is substituted at least partly by sulfur (S) in the substrate.