Pyroelectric materials strontium barium niobate

Strontium barium niobate is a single-crystal material with the tungsten bronze type of structure which is made by the Czochralski method but has yet to find a major use. It has relaxor characteristics of the type shown in Fig. 7.1 which give it a high pyroelectric coefficient and detectivity, but its high permittivity lowers the figure of merit l. ... 

The principal materials used for pyroelectric detectors are members of the TGS group, lithium tantalate, strontium barium niobate, ceramics members of the lead zirconate titanate (PZT) group and, more recently, films of the polymers polyvinyl fluoride (PVF) and polyvinylidene fluoride (PVFj). 

The performance of the pyroelectric detector n strongly determlDed by material properties as well as device parameters. The suitability of FLC potymers for this Idiid of applkatioo has to conqielc with the as yet most widely used pyroelectric compounds such as triglydoc sulfate (TGS). lithium tantalatc (liThO)), strontium barium niobate (SBN). bariumtitanate (BaDO,). FVDF, and PVFi. 

For room temperature operation, a most attractive thermal detector is the pyroelectric element. It is a small capacitor with a dielectric material that possesses a temperature sensitive dipole moment. So far, the most successful dielectric is triglycine phosphate (TGS), particularly if doped with L-alanine. Its Curie point is at 49 °C and, consequently, it must be operated below that temperature. (Above the Curie point, these dielectrics lose their pyroelectric properties.) Other suitable materials include lithium tantalate and strontium barium niobate. The voltage across a capacitor of charge Q is... 

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