Germanates with NdAlGe/sub 2/O/sub 7/ structure:synthesis,LaGaGe/sub 2/O/sub 7/ stucture, absorption-luminescent properies and stimulated radiation of their activator-Nd/sup 3 +/ ions

New germanates of the structure NaAlGe/sub 2/O/sub 7/ have been synthesized. Using the Czochralsky method monocrystals LaGaGe/sub 2/O/sub 7/ and LaGaGe/sub 2/O/sub 7/-Nd/sup 3 +/ are grown, their X-ray diffraction analysis is carried out. Absorption - luminescence properties are studied in detail and at 300 K stimulated radiation of LaGaGe/sub 2/O/sub 7/-Nd/sup 3 +/ crystals is excited.