HPIT project

project coordinator A. Di Cicco

"PRESSURE-INDUCED TRANSITIONS IN STRONGLY CORRELATED ELECTRON SYSTEMS AND IN SIMPLE AND UNDERCOOLED FLUIDS BY MEANS OF X-RAY, NEUTRON, AND RAMAN TECHNIQUES"

The development of advanced experimental techniques for investigating materials under high pressure is having a profound impact in several disciplines ranging from chemistry, earth science, materials science, and physics. High pressure may indeed induce structural and/or electronic phase transitions in several compounds, including simple and molecular fluids, and strongly correlated solid electron systems. Recently, different groups studied the theoretical aspects of such phase transitions [1-2 and refs. therein], while only few experimental data are currently available for systems under these extreme conditions [3-8 and refs. therein]. Further experimental efforts are now timely. The aim of this proposal is to develop suitable in-house experimental techniques for investigating pressure-induced structural and electronic phase transitions. In the framework of the present project, we will develop new high pressure instruments for x-ray diffraction (units of CM and RR), and microRaman spectroscopy (RS unit). Combining these equipments with the instrumentation available within the Partners laboratories, we will be able to perform x-ray and neutron diffraction, and Raman and infrared measurements over a wide pressure and temperature ranges (0-30 GPa, 80-12000 K). The developed instrumentation, together with the synergetic expertise of the Partners, will enable us to investigate different aspects of pressure-induced phenomena, such as: 1) Polymorphism in molecular liquids (water and oxides) and in solid and undercooled liquid metals (Bi, Ga, Ge). 2) Insulator-to-Metal transition in both molecular fluids (I2, Br2, GeI4, SnI4) and strongly correlated solid electron systems (manganites and spinels).

1. P. H. Poole, T. Grande, C. A. Angell, P. F. McMillan, Science 275, 322 (1997).
2. G. Franzese, G. Malescio, A. Skibinsky, S. V. Buldyrev, and H. E. Stanley, Nature 409, 692 (2001).
3. Y. Katayama et al., Nature 403, 170 (2000).
4. O.Mishima, H.E. Stanley, Nature 392, 164 (1998); O. Mishima, Phys. Rev. Lett. 85, 334 (2000).
5. A. Soper and M.A. Ricci, Phys. Rev. Lett. 84, 2881 (2000).
6. A. Congeduti, P.Postorino et al., Phys. Rev. Lett. 86, 1251 (2001).
7. L. Comez, A. Di Cicco, J. P. Itie' and A. Polian, Phys. Rev. B 65, 014114 (2002).
8. A. Congeduti, P.Postorino, P. Dore et al, Phys. Rev. B 63, 184410 (2001)

UP

HPIT: current results and list of relevant publications

• A. Di Cicco, E. Principi, M. Minicucci, S. De Panfilis, A. Filipponi, F. Decremps, F. Datchi, J. P. Itie', P. Munsch, and A. Polian, "Structure of crystalline and amorphous Ge probed by x-ray absorption and diffraction techniques", High Pressure Research 24, 93-99 (2004)
• E. Principi, A. Di Cicco, F. Decremps, A. Polian, S. De Panfilis, and A. Filipponi, "Polyamorphic transition of germanium under pressure", Phys. Rev. B Rapid Communication 69, 201212 (R) (2004)
• E. Principi, F. Decremps, A. Di Cicco, F. Datchi, S. De Panfilis, A. Filipponi, and A. Polian, "Pressure induced phase transitions in amorphous Ge", Phys. Scripta T115 381 (2005)
• M. Minicucci, A. Trapananti, A. Di Cicco, S. De Panflis, and G. Aquilanti, "Cadmium under High Pressure and High Temperature Conditions", Phys. Scripta T115 1056 (2005).
• A.Sacchetti, P.Dore, P.Postorino, A. Congeduti "PRESSURE AND TEMPERATURE DEPENDENCE OF OPTICAL PHONONS IN La(0.75)Ca(0.25)MnO3" J. of Phys. and Chem. of Solids 65 1431 (2004)
• A. Paolone, A.Sacchetti, T.Corridoni, P.Postorino, R.Cantelli "MICRORAMAN SPECTROSCOPY ON LiMn.2O4: WARNINGS ON LASER-INDUCED THERMAL DECOMPOSITION" Solid State Ionics 170 135 (2004)
• M. Cestelli-Guidi, A.Nucara, P. Calvani, P. Postorino, A. Sacchetti, A. Congeduti, M. Piccinini, A. Marcelli, E. Burattini "HIGH-PRESSURE FAR-INFRARED MEASUREMENTS AT SINBAD" Infrared Phys. & Tech. 45 365 (2004)
• P. Postorino, A. Sacchetti, M. Capone, P.Dore "COMPETIVE EFFECTS ON THE HIGH-PRESSURE PHASE DIAGRAM OF MANGANITES" Phys. Stat. Sol. (b) 241 3381 (2004)
• M. Piccinini, M. Cestelli Guidi, A. Marcelli, P. Calvani, E. Burattini, A. Nucara, P. Postorino, A. Sacchetti, E. Arcangeletti, E. Sheregii, J. Polit, A. Kisiel "FAR INFRARED SYNCHROTRON RADIATION SPECTROSCOPY OF SOLIDS IN NORMAL AND EXTREME CONDITIONS" Phys. Stat. Sol. (c) 2 236 (2005)
• A. Paolone, A. Sacchetti, P. Postorino, R. Cantelli, A. Congeduti, G. Rousse "STABILIZATION OF THE ORTHOROMBIC PHASE OF LiMn2O4 BY MEANS OF HIGH PRESSURE" Solid State Ionics 176, 635 (2005)
• M. Ortolani, D. Di Castro, P. Postorino, I. Pallecchi, M. Monni, M. Putti, P. Dore. "CLEAN AND DIRTY SUPERCONDUCTIVITY IN PURE, Al-DOPED, AND NEUTRON IRRADIATED MgB2: A FAR INFRARED STUDY" Phys. Rev. B 71, 172508 (2005)
• A. Paolone, A. Sacchetti, S. Cantelli, P. Postorino. "COMMENTS ON EFFECT OF CHROMIUM SUBSTITUTION ON THE LATTICE VIBRATION OF SPINEL LITHIUM MANGANATE: A NEW INTERPRETATION OF THE RAMAN SPECTRUM OF LiMn2O4" J. Phys. Chem. B 109, 7587 (2005)
• A. Sacchetti, M. Baldini, F. Crispoldi, P. Postorino, P. Dore, A. Nucara, C. Martin., A. Maignan "TEMPERATURE DEPENDENCE OF THE OPTICAL PHONONS IN SrMnO3 MANGANITE: EVIDENCE OF A LOW-TEMPERATURE STRUCTURAL TRANSITION IN THE HEXAGONAL COMPOUND" Phys. Rev. B 72, 172407 (2005)
• P. Dore, P. Postorino, A. Sacchetti, M. Baldini, R. Gianbelluca, M. Angeloni, G. Balestrino "RAMAN MEASUREMENTS ON THIN FILMS OF THE La0.7Sr0.3MnO3 MANGANITE: A DIRECT PROBE OF SUBSTRATE INDUCED EFFECTS" European Phys. J. B 48, 255, (2005)
• A.Sacchetti, P.Postorino, M.Capone "HIGH-PRESSURE PHASE DIAGRAM IN THE MANGANITES: A TWO-SITE MODEL STUDY" New J. Phys. 8, 3 (2006)
• A.Sacchetti, M.Cestelli Guidi, E. Arcangeletti, A. Nucara, P. Calvani, M. Piccinini, A. Marcelli, P. Postorino "Far Infrared Absorption of La1-x Cax MnO3-d at High Pressure" Phys. Rev. Lett. 96, 035503 (2006)
• A.Sacchetti, M. Baldini, P. Postorino, C. Martin., A. Maignan "RAMAN SPECTROSCOPY ON CUBIC AND HEXAGONAL SrMnO3" J. Raman Spect. (submitted 2006 - doi: 10.1002/jrs.1484)
• P. Dore, P. Postorino, A. Sacchetti, A. Congeduti, F.A. Gorelli, L. Ulivi, D.D. Sarma "EVIDENCE OF PHASE SEPARATION IN THE PHASE DIAGRAM OF THE La0.75Ca0.25MnO3 MANGANITE BY INFRARED MEASUREMENTS" J. of Superconductivity (submitted 2006)
• A. Sacchetti, M. Cestelli Guidi, E. Arcangeletti, P. Postorino, A. Nucara, M. Piccinini, P. Calvani, A. Marcelli "High-pressure far-infrared absorption measurements on La1-x Cax MnO3-d by means of synchrotron radiation" Infrared Physics & Technology (submitted 2006)
• M. Cestelli Guidi, A. Sacchetti, , E. Arcangeletti, M. Piccinini, P. Postorino, A. Nucara, A. Marcelli, P. Calvani "PRESSURE DEPENDENCE OF THE PHONON SPECTRUM OF La1-x Cax MnO3-d MANGANITES" Proceedings of SPIE (submitted 2006)
• M.Angeloni, C.Aruta, G.Balestrino, N.G. Boggio, B. Davidson, P.G.Medaglia, A. Tebano, M.Baldini, D. Di Castro, P.Postorino, P.Dore, A.Sidorenko, G.Allodi, R. De Renzi "Preparation and characterization of LaMnO3 thin films grown by pulsed laser deposition" J. Appl. Phys. (submitted 2006)

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