Curie temperatures and dielectric properties of doped and undoped KTiOPO/sub 4/ and isomorphs

The Curie temperatures and dielectric properties of KTiOPO/sub 4/ (KTP), RbTiOPO/sub 4/, KTiOAsO/sub 4/, RbTiOAsO/sub 4/, CsTiOAsO/sub 4/, Ba:KTP, and Ga:KTP were measured with small-signal relative dielectric permittivity ( kappa ) analysis, piezoelectric resonance analysis, and optical second harmonic generation. All the isomorphs and the doped KTP exhibit lower Curie temperatures than KTP, ranging from 637 degrees C for CsTiOAsO/sub 4/ to 955 degrees C for hydrothermally (HT) grown KTP. The Curie-Weiss law is obeyed in all samples. With the exception of CsTiOAsO/sub 4/, all doped and undoped crystals show large dielectric relaxation at frequencies below 100 KHz throughout the temperature range of 500 degrees C-800 degrees C. For the barium-doped KTP, it was found that the Curie temperature decreases with increasing Ba/sup ++/-doping concentration. Barium doping also significantly modifies dielectric and piezoelectric properties of KTP.<
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