DC Ionic Conductivity in KTP and Its Isomorphs: Properties, Methods for Suppression, and Its Connection to Gray Tracking

We study the DC conductivity in potassium titanyl phosphate (KTiOPO4, KTP) and its isomorphs KTiOAsO4 (KTA) and Rb1%K99%TiOPO4 (RKTP) and introduce a method by which to reduce the overall ionic conductivity in KTP by a potassium nitrate treatment. Furthermore, we create so-called gray tracking in KTP and investigate the ionic conductivity in theses areas. A local unintended reduction of the ionic conductivity is observed in the gray-tracked regions, which also induce additional optical absorption in the material. We show that a thermal treatment in an oxygen-rich atmosphere removes the gray tracking and brings the ionic conductivity as well as the optical transmission back to the original level. These studies can help to choose the best material and treatment for specific applications.

Automated summary

This study investigates the DC conductivity in potassium titanyl phosphate (KTP) and its isomorphs, and suggests a method to reduce the overall ionic conductivity in KTP. Gray tracking phenomena are observed in KTP, which leads to decreased ionic conductivity and additional optical absorption. A thermal treatment in an oxygen-rich atmosphere can eliminate gray tracking and restore the ionic conductivity and optical transmission. These findings can guide the selection of materials and treatments for specific applications.