P.hd in Transport in high magnetic fields and low temperaturesTata Institute of Fundamental Research
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P.hd in Transport in high magnetic fields and low temperatures
The Department of Condensed Matter Physics and Material Sciences (DCMP&MS) in its present form exists since 1998. Until 1998, the research was conducted by separate groups in co-operation with each other.
The initial work began in the 1950s with the study of Nuclear Magnetic Resonance and the Knight shift in metals. The activity related to ultrasonic wave attenuation in solids, study of alkali halides etc was also undertaken. In the late seventies, synthesis of nano materials using the sol-gel route was started and marked the beginning of nanosciences in the Institute. Also magnetism in different materials and properties of strongly correlated electron systems were studied. All this activity evolved into the Solid State Physics group. Around mid-sixties, the Low Temperature Physics group was formed. Using adiabatic nuclear demagnetization, temperatures down to 50 mK were achieved. The group studied transport in nobel metals with magnetic impurities. Later, competition between ferromagnetism and spin glass effects in PdAuFe and PdAuMn based systems was investigated down to 20 mK using a commercial dilution refrigerator. In the mid sixties the group also designed and built Mossbauer spectrometers and carried out Mossbauer studies on a variety of systems. The semiconductor related work was started in the mid-sixties as the Solid State Electronics group. The group began with development of discrete Silicon devices and then worked on design and fabrication of bipolar and MOS integrated circuits. Almost in parallel, study of physics and technology of non-crystalline and compound semiconductor materials and devices was initiated.
As time progressed, the activities of the groups grew to keep in step with the latest developments worldwide. In 1998, all the above groups came together to form the DCMP&MS.
The Department carries out a wide range of frontier research activities related to magnetism and superconductivity and semiconductors, nanostructures, thin films and nanomaterials and is backed by many sophisticated equipments and measurement techniques. Though the main emphasis of our work is on fundamental aspects, many of the results have a potential for applications.
In the area of magnetism, our work largely deals with rare earth intermetallics, and related materials. These are known to exhibit a variety of exotic magnetic behaviors such as Kondo insulators, charge density waves, heavy fermions, mixed valence and giant magneto resistance, to name a few. Many Ce, Eu and Gd based compounds exhibiting some of these properties have been found by us. We have an active program on strongly correlated oxides such as the perovskite ruthenates and rare-earth manganites. A state of the art spectrometer for Photoelectron Spectroscopy of solids has been developed and the unusual properties of magnetism of ruthenates and charge density waves in certain Ir based oxides have been studied. Our other areas of research include amorphous and spin disordered systems and oxide spin glasses.
Superconductivity is an area of considerable interest in the department. Among the areas studied in recent years are: co-existence of charge density waves with magnetism and superconductivity, vortex states in type II superconductors and mapping dynamic phase diagram of pinned superconductors. Our discovery of superconductivity in the quaternary Y-Ni-B-C system has made a significant international impact. Recently, Point Contact spectroscopy has been set up. This has been used to establish the two band superconductivity in Y-Ni-B-C, to study the particle size dependence of the superconductivity in Nb nanoparticles as well as to study the degree of spin polarization in several rare earth alloys and oxides.
In the thin film area, a wide variety of thin films of materials including High Tc materials, manganites and ferroelectrics have been synthesized using pulsed excimer laser deposition.
The properties of materials at nano-meter length scales have been an area of active research in the department, resulting in study of structure-property relationship of nanoparticles. In recent years, using dc/rf magnetron sputtering, a variety of metallic nanoparticles and composites have been synthesized and shown to exhibit novel optical and electrical properties.
In semiconductors area, efforts are devoted to study physics, materials and devices related to III-V compound semiconductors and nanostructures like quantum wells, wires and dots, and porous silicon and organic semiconductors. The nanostructures are synthesized by metal organic vapour phase epitaxy (MOVPE). Many optical spectroscopic techniques have been established for probing the quantum structures. The materials have been used in developing strained quantum well diode lasers at 0.98mm and 1.55mm wavelengths. Recently, work on MOVPE grown nitrides and related devices has been initiated. Work on organic semiconductors has probed optical and transport properties of small molecules such as AlQ and polymers PPV. This has resulted in electroluminescent light emitting devices. In our ultrafast laser laboratory, we perform fs time resolved measurements on low dimensional structures of semiconductors, metallic plasmonic crystals, and other materials. Techniques such as upconversion luminescence, four wave mixing, pump-probe reflection/transmission are set up. Also, we study THz radiation generation, detection and spectroscopy using fs lasers.
The Department has extensive facilities for materials synthesis, measurements, and for fabricating structures by optical and e-beam lithography for special measurements and device applications. Work in Soft Condensed Matter has been initiated recently as a new area of focus. Physics at micro Kelvin temperatures will be studied in the near future. The Department has been increasingly interested in both basic and applicable science related to organic semiconductors and nano- and novel materials and devices. A program for upgradation of the laboratories to attain state of the art nanofabrication capability is being undertaken. Photonic crystals, spintronics and solid state based quantum computing are among the topics of interest in the coming years.
At present, DCMP&MS has 24 members on academic staff, and 24 on scientific, 8 on technical-laboratory, and 3 on Administrative staff. Also, we have 14 research scholars working towards PhD. During 1998-2005, 18 PhD theses were completed. We have many young and senior researchers visiting for limited periods.
DCMP&MS offers plenty of opportunity and openings for bright young scientists to do exciting and challenging research in Condensed Matter Physics and applications. We encourage them to apply for suitable positions. All the research activities are backed by many sophisticated equipments and measurement techniques. Though the main emphasis of our work is on fundamental aspects, many of the results have a potential for applications.