Abstract
The conventional photosensor are electric devices utilizing photoconductive, photovoltac, photoemissive and pyroelectric effect, while the pyromagnetic photosensor PPS is a detector based on pyro effect of a temperature dependant magnetic thin film. The PPS with 1.0μm-thickness is prepared by sputtering a temperature sensitive ferrite with low Curie temperature as a target. When the light is radiated to the PPS, the PPS absorbs light energy which causes the reluctance change to the PPS with temperature rise. The PPS shows pulse response to the step input of light and its peak value grows with an increase in light intensity. The reluctance change of a PPS can be read out as an output voltage by a magnetoresistance element. Therefore, the PPS acts as a photo-magnetic transducer. The PPS with a small heat capacity brings about the large reluctance change and a quick response due to the minute temperature change. It is confirmed that the PPS responds to visible rays and infrared rays, so the PPS is useful as a photosensor instead of the electric sensor. The techniques on the preparation of the PPS, the pyro-magnetic characteristics and the light signal read-out are discussed here.
