Preparation of a Low-Curie-Temperature Magnetic Film and Its Use in a Wide-Range Photosensor

Photographic devices utilizing the pyroelectric effect have already been put to practical use. A wide-range photosensor (WRP) is a detector system using the pyromagnetic effect of a low-Curie-temperature magnetic film (LMF) with 1 μm. thickness. When light is directed onto the WRP, the latter absorbs its energy, which causes a magnetization change in the WRP. This change can be read out by a magnetoresistance element and converted into a voltage. The WRP emits a pulse in response to light with a wide range of wavelengths, from visible to invisible, and its peak value depends on the light intensity. Therefore, the WRP can be used in a radio meter and magnetic light remote control, as well as for magnetic infrared communication. This paper describes the preparation of the LMF, Hie construction of the WRP, and the light response characteristics.