Scopul nostru este sprijinirea şi promovarea cercetării ştiinţifice şi facilitarea comunicării între cercetătorii români din întreaga lume.
National Institute for Material Physics, Bucharest, .
E-mail: trimite un mesaj.
Pagina web a instituţiei: http://www.infim.ro
Pagina web personala: http://www.infim.ro/l/180/Mossbauer_Group/Members/Constantinescu_Serban/constantinescu_serban.htm
Nascut(a) in: 1945
Interese: corp solid, mineralogie, efecte de dimensiune si dimensionalitate in materiale magnetice,rezonanta nucleara gama
Detalii:
EDUCATION:
MS in Physics,1969,University of Bucharest, Romania
Ph.D. in Physics 1980 Thesis: "Hyperfine Interactions studied by Mossbauer Spectroscopy"
PROFESSIONAL EXPERIENCE:
1969-1975 Physicist at the same institute.
1975-1982 Research Physicist at the same institute and laboratory.
1982 -present: Reasearch and Senior Research Physicist at Institute of Atomic Physics,Bucharest, Laboratory of Solid State Physics.
1987-1991 Visiting scientist at Institute of Crystallography of Russian Academy of Science (Moscow)
1994 Postdoc. grant at Venice Univ. Italy
2003 Prof. at Valahia University of Targoviste
MEMBERSHIPS AND HONOURS:
1) The Romanian Physical Society
2) The Romanian Catalyse Society
3) The referee of the European Physical Journal B
Details:
Theoretical aspects of the Mössbauer's line shape in the coupled (electric and magnetic)hyperfine interactions:
a) polarized gamma-ray transition probabilities;
b) Mossbauer scattering probability;
c) Blume's stochastic solution of the Mössbauer line shape.
"Magnetic phase transition in compounds with cupled magneto-electric properties."
- Experimental studies on boracite compounds NixFe3-xB7O13 x=0 ÷ 0.6 investigated by Mossbauer spectroscopy, IR spectroscopy; from He-temperature to 600K; magnetic and structural phase transition, displacements of Fe+2, I-1 ions and antiferromagnetic, weak-ferromagnetic orientation problems; some methodological problems of Mossbauer 57Fe spectra.
- Computer programs:
a) simulation and fitting programs for Mossbauer (transmition) spectra for powder and monocrystalline sample with usual and polarized gama ray;
b) to calculate the hyperfine magnetic fields at 57Fe in the boracites.
"Structure and phase transitions studied by resonance experimental technics in ordered and disorder materials."
- The teoretical aspects and experimental investigations of ferroelectric phase transition on (NH4)2SO4:57Fe, Cd+,Hg+; ESR, Mössbauer resonance; low temperature measurements; ferroelectric phase transition; temperature dependence of Debaye- Waller factor.
- Theoretical aspectes and experimental investigations of cation substitution and magnetic phase transition on ferrigehlenites A(Ba,Sr)2Fe2B(Ge,Si)O7 and on synthetic Ba,Sr(La,Nd)-iron-germanates:A3Fe2Ge4O14 and RA2Fe3Ge3O14 (A=Ba,Sr;R=La,Nd); cation-substitution in Thompson cubes and tetrahedral, octahedral positions by +3 ions inequivalence, crystalline chemistry and magnetic ordering problems;room to hellium temperature Mossbauer measurements, dispersion of the electric field gradient values at Mössbauer isotope sites in Ca-gallogermanites structures.
- The distribution of crystalline fields in static disordered media.
- The structural aspects and experimental investigations on minerals (silicates: olivines, ampyboles, etc.), ferrites, etc. crystalline chemistry, temperature and pressure genesis conditions of some geological romanian deposits; role of neighborhood distortion of cation sites; room and low temperature Mossbauer measurements.
- Theoretical aspects of applied Group Theory and Molecular Orbital Theory in the phase transitions.
- Computer programs:
a) to calculate the temperature dependence of Mossbauer-factor in the ferroelectric and paraelectric region (taking into account the soft-mode;
b) to calculate the lattice and ionic electric field gradient in the approximation of point-electric charges and dipoles and respectively in the frame of Molecular Orbital Theory;
c)electic and magnetic hyperfine fields' distribution in static disordered crystalline media
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Publicații selectate:
* L. DUTA, G. DORCIOMAN, A. C. POPESCU, I. N. MIHAILESCU, P. NITA, I. MERCIONIU, A. BIRSAN, I. BIBICU, S. CONSTANTINESCU, N. POPESCU–POGRION, Structural investigations on electrodes - electrolytes systems for intermediate temperature solid oxide fuel cell applications, OPTOELECTRONICS AND ADVANCED MATERIALS – RAPID COMMUNICATIONS, vol. 6, 11-12, 2012.
* Maria Nicoleta Grecu, Serban Constantinescu, Doina Tarabasanu-Mihaila, Daniela Ghica, and Ion Bibicu, Spin dynamics in 57Fe-doped TiO2 anatase nanoparticles, Phys. Status Solidi B 248, 12, 2011.
* Turcu F, Simon S, Constantinescu S.,Grecu N., Iuga D, "Stuctural changes of pezoelectric La3Ga5SiO14 induced by paramagnetic ions revealed by 71Ga multiple quantum magic angle spinning" , Elsevier, Sol. Stat. Mag. Res., 36, 2009.
* D. Barb, S. Constantinescu, S. Nistor, D. Tarina, Mossbauer Spectroscopy on 57Fe:NaCl crystals, Hyperfine Interactions, 53, 1990.
* D.Barb, S.Constantinescu and D.Tarina, 57Fe Mössbauer Spectroscopy on Disordered Crystalline Media with Ca-Gallogermanate Type Structure, II Below the Magnetic Ordering Temperature, Hyperfine Interactions, 96, 1995.
* D.Barb, S.Constantinescu and D.Tarina, 57Fe Mossbauer Spectroscopy on Disordered Crystalline Media with Ca-Gallogermanate Type Structure, I In Paramagnetic Region, Hyperfine Interactions, 96, 1995.
* D. Barb, S. Constantinescu, D. Tarina, I.S. Lyubutin, B.V. Mill, V.G. Terziev, T.D. Dmitrieva and A.V. Butashin, Magnetic hyperfine fields in ferrigehlenttes, Hyperfine Interactions, 50, 1989.
* S. Georgescu, S. Constantinescu, A. M. Chinie, A. S. Stefan, O. Toma, I. Bibi, Optical and Mossbauer studies on YAG:Eu nanocrystals synthesized, SPIE Proceedings, 6785, 2007.
* V. V. Grecu, S. Constantinescu, Maria Nicoleta Grecu, Rodica Olar, Mihaela Badea and Rodica Turcu, Magnetic characterization of some nanometric i, Hyperfine Interactions, 183, 2008.
* S. Constantinescu, L. Diamandescu, I. Bibicu, D. Tarabasanu-Mihaila, M. Feder,, Hyperfine interactions and dynamics characteristics of 119Sn in xSnO2-(1-x)a-Fe2O3 nanoparticle system, Hyperfine Interactions, 184, 2008.
* S. Constantinescu, I. Mercioniu, N. Popescu-Pogrion , Mathematical model for uniform huge grains growth, Journal of Optoelectronic and Advanced Materials, 10 (11), 2008.
* B.S. Vasile, Cristina Ghitulica, Nicoleta Popescu-Pogrion, S. Constantinescu , Ionel Mercinoiu, Raluca Stan, Ecaterina Andronescu, Structural Investigations on Yttria - Doped Zirconia Nanopowders Obtained by Sol-Gel Method, Journal of Optoelectronic and Advanced Materials, 9 (12), 2007.
* E. Burzo, I., Balasz, S. Constantinescu, I.G. Deac, Grain boundary effect in highly ordered Sr2FeMoO6, North Holland Elsevier, Journal of Magnetism and Magnetic Materials, 316, 2007.
* S. Constantinescu, Distribution of electric and magnetic hyperfine fields in Fe-rich gallo-germanates, SPRINGER-NETHERLAND, Hyperfine Interactions, 168, 2006.
* M. Raekers1,*, K. Kuepper1,#, H. Hesse1, I. Balasz2, I. G. Deac2, S. Constantinescu3 , E. Burzo2,, Investigation of chemical and grain boundary effects in highly ordered Sr2FeMoO6: XPS Mössbauer studies, Journal of Optoelectronics and Advanced Materials (ISSN 1454-4164), 8, 2006.
* M.N. Grecu, S. Constantinescu, V.V. Grecu, Lattice dynamics in ammonium sulphate: EPR and Mössbauer results, ISBN: 972-98802-0-4, A.G.Feio and J.G. Moura, Proceeding of 30th AMPER 2000 on Magnetic Resonance and Related Phenomena, VI, Lisbon, Portugal, 2001.
* L.Gheorghe, S. Georgescu, S. Constantinescu, I. Mateescu, L. Diamandescu, L. Dumitrache and E. Borca, Synthesis, growth and characterisation of langasit crystals, ISBN: 0-7803-7583-1, Proceeding of 2002 IEEE International Ultrasonics Ferroelectrics and frequency Control Society, Munich, Germany, 2002.
* E.D. Ion, S. Constantinescu, M. Bunescu, R.Ramer, Eu-Doped _PtT ceramics. I Preparation and structural investigation, Taylor&Francis Journals, Ferroelectrics, 294, 2003.
* S. Constantinescu , Gh. Udubasa and S. Calogero, 57Fe Mössbauer Spectroscopy on Two Romanian Carpathian Pumpellyites, Journale de Physique I France, 7, 1997.
* D. Barb, S. Constantinescu and D. Tarina, Electric Field Gradients at 57Fe Nuclei in the Sr3Fe2Ge4O14 Trigonal Germanate, Journale de Physique I France, 7, 1997.
* S. Constantinescu - D. Tarina, Crystal-chemistry aspects and electric-field-gradient (EFG) dispersion in Ca-gallogermanate-type structures studied by Mössbauer spectroscopy, European Physical Journal B, 13, 2000.
* S. Constantinescu - M.N. Grecu, The Mössbauer and magnetic resonances investigations of structural phase transitions in K2ZnCl4crystals, Eur. Phys. J. B, 13, 2000.