Sunil K. Sinha

Professor of Physics
Ph.D. Cambridge

Mailing address:
DEPARTMENT OF PHYSICS
UNIVERISTY OF CALIFORNIA SAN DIEGO
9500 GILMAN DRIVE
LA JOLLA CA 92093-0354

Email: ssinha@physics.ucsd.edu

Website: Sinha Group

Teaching

Fall quarter, 2001
Physics 239, Special Topics: X-Ray and Neutron Scattering

Winter Quarter, 2002
Physics 2A, Introductory Mechanics

Research

My group's research is concerned with studying the structure and dynamics of Condensed Matter using the techniques of X-Ray and Neutron Scattering.  Neutrons and X-Rays from Synchrotron Radiation sources are powerful tools to study matter with at length scales ranging from the nanoscopic to the mesoscopic. We have ongoing programs in both hard and soft Condensed Matter.

Our research in the hard Condensed Matter area includes novel magnetic and superconducting materials, in particular magnetic films and multilayers, Giant Magnetoresistance (GMR) devices and Exchange Biased systems, artificially nanostructured magnetic materials such as magnetic dot and hole arrays, the so-called Colossal Magnetoresistance (CMR) compounds, and High-Temperature Superconductors. We study properties such as their magnetic and chemical structure, the existence of polarons and other types of combined lattice/electronic effects, such as charge density waves  or orbital ordering. We also study phonons in these materials, and in the case of the thin film systems,  how the structural and magnetic disorder at interfaces (e.g. roughness) affects their magnetic and transport properties.

In the soft condensed Matter area, our research is concerned with  molecular liquid films, polymer films and interfaces in polymeric systems, which are very relevant at the molecular level, to properties such as adhesion, lubrication and coatings. We use X-Rays and Neutrons to study the fluctuations on the surfaces of polymer films to determine how interactions with the substrate affect these surfaces, and in particular how such fluctuations freeze out as the glassy state is approached.  There is indirect evidence that the properties of liquids in confinement differ remarkably from those of the bulk liquid. We study how the structure and dynamics of liquids and polymers when they are confined between surfaces a few molecular diameters apart are changed from those of the same liquids in the bulk.

Since joining the Physics Faculty at UCSD recently, I am in the process of setting up a laboratory at UCSD for preparing and characterizing samples which will include an x-ray machine,light-scattering and other equipment. The advanced characterization of these samples will however be done at Neutron Scattering Facilities, such as that at Los Alamos National Laboratory in New Mexico, or Synchrotron X-Ray Scattering Facilities such as the Advanced light Source (ALS) at Berkeley or the Advanced Photon Source (APS) at Argonne National Laboratory near Chicago, Illinois. Visits to these facilities to do experiments typically last 1 week to 10 days. Often experiments are done collaboratively with other groups (at UCSD and elsewhere) on samples of interest prepared by them but  which can be uniquely studied using our techniques.

I have taught several introductory graduate level courses in Neutron and X-Ray scattering. To download my course notes, you can look up

http://www.dep.anl.gov    and click on National Neutron and X-Ray School

Selected Publications ( Soft Condensed Matter)

M.K.Sanyal, S.K.Sinha, K.G.Huang and B.M.Ocko, X-ray Scattering study of Capillary Wave Fluctuations at a Liquid Surface, Phys. Rev. Lett. 66, 628 (1991)

M.Tolan, O.H.Seeck, J.-P. Schlomka, W.Press, J.Wang, S.K. Sinha, Z.Li, M.Rafailovich, and J.         

Sokolov, Evidence for Capillary Waves on Dewetted Polymer Film Surfaces: A Combined X-ray and Atomic Force Microscopy Study, Phys. Rev. Lett. 81, 2731 (1998)

Z. Li, M. Tolan, T. Hohr, D. Kharas, S. Qu, J. Sokolov, M.H. Rafailovich, H. Lorenz, J.P. Kotthaus, J. Wang, S. K. Sinha and A. Gibaud, Polymer Thin films on Patterned Si Surfaces, Macromolecules 31, 1915, (1998).

J. Wang, M. Tolan, O.H. Seeck , S.K. Sinha, O. Bahr, M.H. Rafailovich, and J. Sokolov, "Surfaces of Strongly Confined Polymer Thin Films Studied by X-ray Scattering," Phys. Rev. Lett., 83, 564 (1999).

K.Shin, Y.Pu, M.H.Rafailovich, J.Sokolov, O.H.Secck, S.K. Sinha, M.Tolan and R. Kolb,

Correlated Surfaces of Free-standing Polystyrene Thin Films, Macromolecules 34, 5620, (2001) 

J.Wang, A.K.Sood, P.V.Satyam,Y.P.Feng, X.Z.Wu,Z.H.Cai,W.B.Yun and S.K.Sinha,X-ray Fluorescence Correlation Spectroscopy: A method for Studying Particle Dynamics in Condensed Matter, Phys. Rev. Lett. 80, 1110 (1998).

S.K. Sinha, Small Angle Scattering from Porous Materials, Book Chapter in Physics of Porous Media, P.Z. Wong, Ed., Academic Press, 1999).

H.J.Kim, A.Ruhm, L.B.Lurio, J.K.Basu,J.Lal, D.Lumma, S.G.J.Mochrie, and S.K.Sinha, Surface Dynamics of Polymer Films (submitted)

O.H.Seeck, H.J.Kim, D.R.Lee, D.Shu, I.Kaendler, J.K.Basu and S.K.Sinha, Observation of Thickness Quantization in Liquid Films Confined to Molecular Dimensions (submitted)

 Selected Publications (Hard Condensed Matter)

R.M. Osgood, S.K. Sinha, J.W. Freeland, Y.U. Idzerda, and S.D. Bader, "X-ray Scattering from Magnetically and Structurally Rough Surfaces," J. Magn. Magnetic Materials, 198-199, 698 (1999).

C.S. Nelson, G. Srajer, J.C. Lang, C.T. Venkataraman, S.K. Sinha, H. Hashizume, N. Ishimatsu, and N. Hosoito, "Charge-Magnetic Roughness Correlations in an Fe/Gd Multilayer," Phys. Rev.B, 60, 12 234, (1999).

S.K.Sinha, The Impact of Synchrotron Radiation on Nanoscience, Appl.Surf. Sci. 182, 176 (2001)

S.A. Stepanov and S.K. Sinha, "X-ray Resonant Reflection from Magnetic Multilayers: Recursion Matrix Algorithm," Phys. Rev. B , 61, 15302, (2000).

L. Vasiliu-Doloc, S. Rosenkranz, R. Osborn, S.K. Sinha, J.W. Lynn, J. Mesot, O. H. Seeck, A.J. Fedro, and J.F. Mitchell, "Charge Melting and Polaron Collapse in La_1.2Sr_1.8Mn₂O₇," Phys. Rev. Let 83, 4393 (1999).

R. Osborn, S. Rosenkranz, D.N. Argyriou, L. Vasilliu-Doloc, J.W. Lynn, S.K. Sinha, J.F. Mitchell, K.E. Gray, and S.D. Bader, "Neutron Scattering Investigation of Magnetic Bilayer Correlations in La_1.2Sn_1.8Mn₂O₇," Phys. Rev. Lett. 81, 3964, (1998).

Z.Islam, S.K.Sinha, D.Haskell, J.C.Lang, G.Srajer, D.R.Haeffner, B.W.Veal, and H.A.Mook, X-Ray Diffraction Study of Charge Density Waves and Oxygen Ordering in YBa2Cu3O6+x (submitted)

Selected publications (General):

S.K. Sinha and R. Pynn, "Diffuse X-ray and Neutron Reflection from Surfaces and Interfaces," in  Local Structure from Diffraction, S.J.L. Billinge and M.F. Thorpe, Eds., (Plenum Press, New York, 1998.

S.K.Sinha, E.B.Sirota, S.Garoff and H.B.Stanley, X-ray and Neutron Scattering from Rough

Surfaces,Phys. Rev. B 38, 2297 (1988)

S.K. Sinha, "Theory of Inelastic X-ray Scattering from Condensed Matter, J.Phys. Cond. Matter 13, 7511 (2001)

S.K. Sinha, "New Developments in the Application of Synchrotron Radiation to Material Science," Jpn. J. Appl. Phys., 38, 1, (1999).

Research Group

Hyunjung Kim

Joydip Basu     

Judith St. Austin (Secy.)

Postdoctoral Researchers in my group (past 5 years) and their current affiliations:

Dong Ryeol Lee (Argonne National Laboratory)   

Oliver Seeck (KFA, Julich, Germany)   

Xiao Zhong Wu (IBM Almaden) 

Hong Zhao (Lucent Technologies)                

Jin Wang (Argonne National Laboratory)

Yiping Feng (Lucent Technologies)

Zahirul Islam (Argonne National Laboratory)

Parlapalli Satyam (Inst. Physics, Bhubaneshwar, India).