An Ultrasonic Sensor for Process Modeling and Proces Control of Ceramic Superconductors
This research demonstrates the feasibility of utilizing nondestructive ultrasonic sensors to monitor the effects of oxygen content, processing time and temperature on the resultant mechanical, structural, and electrical properties of high temperature ceramic superconductors. Ultrasonic velocity changes, as a function of processing time and temperature, have clearly been shown to indicate the transformation between orthorhombic and tetragonal phases in Y-Ba-Cu-O.
On the Disorder of LiNbO3 Crystals
Results of investigations of the absorption, electrical conductivity, and photoconductivity of LiNbO3 are presented. They are explained by a model being similar to the anti-Frenkel disorder and by the formation of F2 centres during the reduction of the crystals. The model also illustrates the dependence of the Curie temperature on the Li:Nb ratio and optically induced refractive index inhomogeneities. 
 
 
 
Es werden Ergebnisse von Untersuchungen der Absorption, der elektrischen Leitfahigkeit und der Phtoleitfahigkeit von LiNbO3 vorgelegt. Sie werden mit einem der Anti-Frenkel-Fehlordnung ahnlichen Model und der Bildung von F2-Zentren bei der Reduktion der Kristalle erklart. Das Modell macht zugleich die Abhangigikeit der Curie-Temperatur vom Li:Nb-Verhaltnis und optisch induzierte Brechzahlinhomogenitaten verstandlich.
Correlation of Reduction in Optically Induced Refractive‐Index Inhomogeneity with OH Content in LiTaO3 and LiNbO3
It has recently been demonstrated that crystals of LiTaO3 and LiNbO3 can be made more resistant to optically induced refractive‐index inhomogeneities caused by laser irradiation by annealing the crystals in the present of an electric field. The explanation given for the improvement was that some impurity entered the crystal during the annealing cycle, modifying the conductivity of the material. Additional data presented here suggest that the impurity is hydrogen. The exact mechanism by which the susceptibility to index inhomogeneity is reduced is not understood at this time.