TeO 2 crystal has excellent acousto-optic properties and double  decay properties of high natural abundance of 130 Te isotope. It can be used in high-performance acousto-optic devices and also for the research of neutrino and dark matter. Recently, the above applications raise the requirements for the size and quality of TeO 2 crystal. Structure and physical properties of TeO 2 crystal are briefly introduced in this article, and then the recent progress on the preparation of large sized TeO 2 crystal with high quality and its application in infrared devices are reviewed. Finally, its preparation and application in future of TeO 2 crystal are discussed.

No abstract

The magnetotransport measurement is performed on a GaN/AlxGa1-xN heterostructure sample in a low temperature range of 1.4-25 K and at magnetic fields ranging from 0 T up to 13 T. Magnetoresistance of a two-dimensional electron gas confined in the heterostructure is investigated. The negative magnetoresistivity in the whole magnetic field range originates from the electron-electron interactions (EEIs), while the positive magnetoresistivity in the high field range results from the parallel conductance. The EEI correction terms, as well as the concentration and mobility of the parallel channel are obtained by fitting the experimental data. Furthermore, another method of calculation is used to check their accuracy.