Accession Number : AD0663734

Title :   A STUDY OF THE PHYSICAL PROPERTIES OF HIGH-TEMPERATURE SINGLE CRYSTALS.

Descriptive Note : Final rept. 16 May 62-30 Jun 67,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE CRYSTAL PHYSICS LAB

Personal Author(s) : Smakula,Alexander

Report Date : 30 SEP 1967

Pagination or Media Count : 128

Abstract : A great variety of single crystals were grown and their physical properties studied. Crystals of metal oxides MnO, CoO, NiO, and mixed crystals of MnO-CoO, MnO-NiO, and CoO-NiO were grown by flame fusion and their electrical properties (dielectric constant and conductivity) and optical properties (refraction and absorption) as a function of frequency and temperature determined. The paraelectric properties of KTaO3 and the ferroelectric properties of KTaO3-NaTaO3 and KTaO3-KNbO3 were investigated as a function of composition and temperature. The dielectric properties of alkali halides, thallium halides, copper halides, and alkaline earth fluorides were measured over a wide frequency and temperature range. In semiconducting crystals (Si, Ge, and GaAs), dielectric anomalies were detected at low temperatures. The method for crystal growth of fluorides was improved, and single crystals of KMgF3, RbMnF3, and YLiF4 were grown and their optical properties determined. The perfection of crystals was studied by ultraviolet and infrared absorption, by high precision lattice constant, and high precision density measurements. The mechanical properties were studied by microhardness measurement. The microhardness of mixed crystals was studied in particular. (Author)

Descriptors :   (*REFRACTORY MATERIALS, *SINGLE CRYSTALS), (*CRYSTAL GROWTH, REFRACTORY MATERIALS), DIELECTRIC PROPERTIES, ELECTRICAL CONDUCTIVITY, REFRACTION, ABSORPTION SPECTRA, ULTRAVIOLET SPECTRA, VISIBLE SPECTRA, INFRARED SPECTRA, HARDNESS, MAGNETIC PROPERTIES, MANGANESE COMPOUNDS, COBALT COMPOUNDS, NICKEL COMPOUNDS, OXIDES, SOLID SOLUTIONS, POTASSIUM COMPOUNDS, SODIUM COMPOUNDS, TANTALUM COMPOUNDS, NIOBATES, ALKALI METAL COMPOUNDS, THALLIUM COMPOUNDS, COPPER COMPOUNDS, HALIDES, ALKALINE EARTH COMPOUNDS, FLUORIDES, SEMICONDUCTORS, YTTRIUM COMPOUNDS

Subject Categories : Ceramics, Refractories and Glass
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE