My first constact with Materials Science and Engineering (MSE) research was in the second semester of 1992 when several seminars on crystal growth techniques and semiconductors characterization were given by Prof. Dr. S. A. Lopez- Rivera (University of Los Andes, ULA, Mérida, Venezuela) during a visit made to the Physics Department of the Industrial University of Santander , UIS, Colombia. A semester later I started my research work on diluted semimagnetic semiconductors (D. Reyes Ardila, Production of II-VI compounds and their solid solutions with magnetic ions using the Bridgman-Stockbarger and the chemical transport methods. Undergraduate Work, U.I.S.- Colombia,1993) under the advisory of Prof. Dr. J. Martínez (UIS, Colombia), co-advisory of Prof. Dr. A. López Zagarra (UIS, Colombia) and Prof. Dr. Witold Giriat (IVIC, Venezuela).

   In 1994 I started the search of the MSc degree in MSE in the Physics Institute of the U. of São Paulo at São Carlos (IFSC-São Carlos-SP) , Brazil, where I started a research work on some oxide single crystal fibers under the advisory of Prof. Dr. José Pedro Andreeta (D. Reyes Ardila , Crystal Growth and Characterization of SrTiO₃, SrTi_1-XRu_XO₃ and Sr₂RuO₄ single crystal fibers M.Sc. Thesis, DFCM-IFSC-USP, Brazil, 1996), co-advisory of Prof. Dr. A. C. Hernandes and collaborations of Prof. Dr. S. L. Cuffini and Prof. Dr. Y. P. Mascarenhas. I got a M.Sc. degree in Materials Science and Engineering in 1996.

   In 1996 I started a PhD in MSE developing activities on single crystal fiber growth and characterization of several host oxides in different crystal growth atmospheres and at medium pressure. I got a Ph. D. degree in 2001. Actual researh collaborations are maintained with the Spectroscopy Labs. and the Ceramics & Crystal growth Labs. of the IFSC-USP with financial support of Brazilian Research Agencies FAPESP, CNPq, CAPES and PRONEX.

Some of the refeered international publications that have been reported on this reasearch are listed below.

D. Reyes Ardila, J.P. Andreeta and H. C. Basso. Preparation, microstructural and electrical characterization of SrVO₃ single crystal fiber, J. Crystal Growth 211 (2000) 313.

Abstract : Two different processing routes have been adapted for the single-crystal fiber growth of strontium vanadate (SrVO₃) by the laser-heated pedestal growth (LHPG) method. These processes use only one step for calcination, sintering, melting, reduction and solidification of the raw material. Single-crystal fibers have been grown from mixtures of SrCO₃, VO₂ and V₂O₅ powders in the cylindrically compacted powders geometry, appropriate molar ratio and controlled atmosphere....

D. Reyes Ardila, M.R.B. Andreeta, S.L. Cuffini, A.C. Hernandes, J.P. Andreeta and Y.P. Mascarenhas, Laser heated pedestal growth of Sr₂RuO₄ single-crystal fibers from SrRuO₃, J. Crystal Growth 177 (1997) 52.

Abstract: We report the single-crystal growth of Sr₂RuO₄ by the laser heated pedestal growth (LHPG) method. The fibers obtained were up to 30 mm in length and around 0.8 mm in diameter. They crystallized with the K₂NiF₄ structure, space group I4/mmm and with lattice parameters a = 3.869(1) angst, c = 12.745(5) Å. They were easily cleaved along the growth axis, parallel to the (001) plane. The single-crystal fibers were characterized by scanning electron microscopy, electron probe micro-analysis and X-ray diffraction.

D. Reyes Ardila, J. P. Andreeta, C. T. M. Ribeiro, and M. Siu Li, Improved laser-heated pedestal growth system for crystal growth in medium and high isostatic pressure environment, Rev. Sci. Instrum. 70 (1999) 4606.

Abstract: A modified apparatus for single-crystal-fiber growth in an isostatic gaseous environment and for a large range of pressure (100 mbar up to 100 bar) using a floating-zone-type method known as laser-heated pedestal growth is described. The difficulties and advantages of its design are discussed through examples of crystal growth of some oxide materials.

D. Reyes Ardila, M.R.B. Andreeta, S.L. Cuffini, A.C. Hernandes, J.P. Andreeta and Y.P. Mascarenhas, Single-crystal SrTiO₃ fiber grown by laser heated pedestal growth method: influence of ceramic feed rod preparation in fiber quality, Mat. Res. 1 (1998) 11.

Abstract: The rapidly spreading use of optical fiber as a transmission medium has created an interest in fiber-compatible optical devices and methods for growing them, such as the Laser Heated Pedestal Growth (LHPG). This paper reports on the influence of the ceramic feed rod treatment on fiber quality and optimization of ceramic pedestal processing that allows improvements to be made on the final quality in a simple manner. Using the LHPG technique, transparent crack-free colorless single crystal fibers of SrTiO₃ (0.50 mm in diameter and 30-40 mm in length) were grown directly from green-body feed rods, without using external oxygen atmosphere.

C. T. M Ribeiro, D. Reyes Ardila, J. P Andreeta, M. Siu Li . Effects of isostatic oxygen pressure on the crystal growth and optical properties of undoped and Er³⁺-doped Ca₃(VO₄)₂ single-crystal Fibres, Adv. Mater. Opt. Electron. 10 (2000) 9.

Abstract: The influence of the isostatic oxygen pressure as a crystal growth atmosphere on the optical and structural properties of undoped and erbium-doped calcium orthovanadate single-crystal fibres was studied by optical absorption, photoluminescence, energy-dispersive X-ray analysis and X-ray powder diffraction techniques. Relationships between the oxygen pressure used during the crystal growth and some optical and structural parameters are established. Through an oxygen vacancy model the effects of the crystal growth conditions on the physical properties of the material are inferred

You can find a short materials science glossary related to my actual research work and some pictures of crystals that I am currently growing.