Growth and EPR properties of NdVO4, HoVO4 and NdVO4 single crystals
|Slawomir M. Kaczmarek 1, Marek Berkowski 2, Grzegorz Leniec 1, Michał M. Głowacki 2, Tomasz Skibiński 1|
1. West Pomeranian University of Technology, Szczecin (ZUT), Szczecin 70-310, Poland
Single crystals of NdVO4, HoVO4 and ErVO4 were grown by the Czochralski method in an inductively heated iridium crucible of 40 x 40 mm and with an passive afterheater. Starting materials with 4N purity were heated at 1000 °C (Nd2O3, Ho2O3 and Er2O3) or at 300°C V2O5 for 6 hours before weighing, mixing and melting. Due to evaporation of vanadium from the melt during crystal growth process  composition of starting oxides was 1 mol.% shifted towards higher concentration of V2O5. Single crystals with 20 mm diameter were grown on an iridium 2 mm rod with pulling rate of 3-4 mm/h and a rotation of 4-6 rpm. Crystals were grown under ambient pressure in a nitrogen atmosphere. During crystallization strong tendency to spiral growth was observed, especially for HoVO4. In spite of lack of crystal seed most crystals started to grow along direction close c-axis with a- and b-planes (cleavage planes) on the side. Obtained single crystals were transparent with strong coloring – violet for NdVO4, yellow for HoVO4 and pink for ErVO4.
EPR spectra of the three well oriented crystals were recorded on a conventional X-band Bruker ELEXSYS E 500 CW-spectrometer (Bruker Analytik GmbH, Rheinstetten, Germany) operating at 9.5 GHz with a 100-kHz magnetic field modulation. The first derivative of the absorption spectra has been recorded as a function of the applied magnetic field. Temperature dependence of the EPR spectra of the samples in the 3–300 K temperature range was recorded using an Oxford Instruments ESP nitrogen-flow cryostat (Oxford Instruments Ltd., Witney, UK). EPR-NMR program was applied to recognize spin Hamiltonian parameters of the rare-earth ions .
 K. Oka, H. Unoki, H. Shibata, H. Eisaki, Journal of Crystal Growth 286 (2006) 288–293
 M.J. Mombourquette, J.A. Weil, and D.G. McGavi: EPR-NMR User’s Manual (Department of Chemistry, University of Saskatchewan, Saskatoon, Canada, 1999).
Presentation: Oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, General Session 2, by Slawomir M. Kaczmarek
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17
Submitted: 2013-04-22 22:45 Revised: 2013-07-19 23:15