PYROPHOTOSENSOR UTILIZING THERMALLY-SENSITIVE MAGNETIC THIN-FILM

The pyre photosensor PPS with 1.0 mu m-thickness is ii device utilizin g the magnetic property of the thermally-sensitive ferri magnetic thin film with low Curie temperature. The conventional photo-magnetic semi conductor using a thick film with 55 mu m-thickness has a slow respons e;md a large size, while the PPS is characterized by a quick pulse res ponse and a high sensitivity. When light is radiated to the PPS, the P PS absorbs light energy which causes the reluctance change to the PPS. The reluctance change can be read out by ii magnetoresistance element and it is converted into voltage of which the peak value grows with a n increase in illuminance. The PPS is useful as a magnetic sensor inst ead of the electric photo sensors.