Crystal Growth of Quantum Magnets in the Rare-Earth Pyrosilicate Family R2Si2O7 (R = Yb, Er) Using the Optical Floating Zone Method
Department of Physics, Colorado State University, 200 W. Lake St., Fort Collins, CO 80523-1875, USA
Department of Physics, 500 W. University Ave, The University of Texas at El Paso, El Paso, TX 79968, USA
Author to whom correspondence should be addressed.
Crystals 2019, 9(4), 196; https://doi.org/10.3390/cryst9040196
Received: 23 March 2019 / Revised: 31 March 2019 / Accepted: 2 April 2019 / Published: 7 April 2019
(This article belongs to the Special Issue Optical Floating Zone and Crystals Grown by this Method)
We report on the crystal growth of rare-earth pyrosilicates,
Si O for R = Yb and Er using the optical floating zone method. The grown crystals comprise members from the family of pyrosilicates where the rare-earth atoms form a distorted honeycomb lattice. C-Yb Si O is a quantum dimer magnet with field-induced long range magnetic order, while D-Er Si O is an Ising-type antiferromagnet. Both growths resulted in multi-crystal boules, with cracks forming between the different crystal orientations. The Yb Si O crystals form the C-type rare-earth pyrosilicate structure with space group and are colorless and transparent or milky white, whereas the Er-variant is D-type, , and has a pink hue originating from Er . The crystal structures of the grown single crystals were confirmed through a Rietveld analysis of the powder X-ray diffraction patterns from pulverized crystals. The specific heat of both C-Yb Si O and D-Er Si O measured down to 50 mK indicated a phase transition at 1.8 K for D-Er Si O and a broad Schottky-type feature with a sharp anomaly at 250 mK in an applied magnetic field of 0.8T along the c-axis in the case of C-Yb Si O .