838. Applications of ion pumping, titanium-getter pumping and cryogenic pumping in the construction of evaporation plant for the study of thin films, electron guns for the evaporation of the source: A Varon,Revue de la Société Royale Belge des Ingénieurs et des Industriels, (5), May 1965, 257, (in French)

Abstract

We report that β′-Gd2(MoO4)3 crystals have been grown by the Czochralski (CZ) method. We studied the growth conditions of β′-Gd2(MoO4)3 crystal. A comparison between the resistance-heated method and radio frequency induction-heated method is described. Also, the in situ observation of the domain structure by the microscope and by synchrotron radiation X-ray topography under the conditions of DC polarization voltage and temperature change were carried out. Experiments showed that multidomain structure including ferroelectric and ferroelastic domains occurred in β′-Gd2(MoO4)3 crystal. Usually ferroelectric domains appeared in the as-grown crystal and ferroelastic domains appeared in the polished thinner piece. Both ferroelectric and ferroelastic domains disappeared when the temperature of the crystal piece was higher than the Curie temperature TC and they could be reproduced when the temperature of the crystal piece was lowered below TC. When a DC polarization voltage ranging from 150 to 500 V was applied on a c-axis β′-Gd2(MoO4)3 piece having a thickness of 0.5 mm, the multidomain would gradually transform to a single domain. This result means that it is possible to make a periodically poled β′-Gd2(MoO4)3 crystal.