Hyperfine structure associated with the dominant radiation‐induced trapped hole center in RbTiOPO₄ crystals

Abstract

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) have been used to characterize the complex hyperfine patterns exhibited by the primary radiation-induced trapped hole center in single crystals of RbTiOPO 4 (commonly referred to as RTP). These defects are produced at 77 K by irradiating with X-rays, and they are destroyed by raising the temperature above approximately 170 K. In this center, the hole resides on a bridging oxygen ion located between two titanium ions and is stabilized by a nearby rubidium vacancy. Hyperfine splittings from interactions with one rubidium neighbor and one phosphorus neighbor are resolved in the EPR spectra. The ENDOR spectra show one larger phosphorus interaction and four smaller phosphorus interactions. Principal values and principal axis directions for this larger phosphorus interaction are obtained from the ENDOR angular dependence.

Electron paramagnetic resonance study of platinum impurity ions in KTiOAsO4 crystals

“…The present paper describes a platinum-related trapped hole center that is produced in KTiOAsO 4 crystals by an X-ray irradiation at either room temperature or 77 K. Trapped hole centers in KTP, RTP, and KTA crystals [8,9,[11][12][13][14] usually consist of holes trapped on oxygen ions with either a potassium vacancy, a rubidium vacancy, or an impurity nearby. The present hole center has a much different model, and its interpretation follows the work of Garces et al [15] in KTP.…”