Electronic structure, vibrational properties and spin dynamics of some selected magnetic systems
Abstract
In this presentation, I will briefly present some of the interestingstatic and dynamical aspects of few selected magnetic insulators andmetals.The electronic structure, vibrational properties and interestingdielectric nature of perovskites A(Ca,Sr,Ba)MnO3 will be discussed fromfirst principles, particularly the possibility to engineer a transitionmetal driven type-I multiferroicity in these oxides[1] will be specified.Then I will highlight some dielectric properties of Mn -doped SrTiO3 [2].In short, the quasiparticle electronic structure of thin films of localmoment systems like GdN and GdS will be reviewed [3]. Also I will presentsome of the results of the spin dynamics simulation for the magnetizationdynamics in an synthetic antiferromagnet subjected to a short pulse,particularly in terms of experimentally observed inertia like behavior init’s magnetization dynamics[4]. Finally an effort to develop a generalformalism to describe the experimentally observed spin dynamics infemto-second time scale will be discussed [5].References:[1] S. Bhattacharjee, E. Bousquet and Philippe Ghosez , Phys. Rev.Lett.,102, 117602 (2009)[2] Debraj Choudhury, P. Mandal, A. Sundaresan, Umesh V. Waghmare,Satadeep Bhattacharjee, R. Mathieu, P. Lazor, Olle Eriksson, B. Sanyal,P. Nordblad, Ajay Sharma, S. V. Bhat, O. Karis, D. D. Sarma, cond-mat.,1009.4792, (2010),[3] S. Bhattacharjee and S.M Jaya, Eur. Phys. J. B 49, 305-311 (2006) .[4] S. Bhattacharjee, A. Bergman, A. Taroni, J. Hellsvik, B. Sanyaland O. Eriksson, arXiv:1109.1414, (2011).[5] S. Bhattacharjee, L.Nordstrom and J. Fransson (in manuscript).
11/10/2011 at 11:00 am
S M Yusuf, Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai
General Seminar
Lecture Hall Block A, Institute of Physics
Document Date:
Functional Magnetic Materials: Fundamental and Technological Aspects
Matter Wave Interferometry with Ultra-cold Atoms: Fundamental Physics and Applications
Abstract
This talk is a limited overview of the principles and techniques ofinterferometry with ‘matter waves’ – quantum interferometry to be moreprecise. I will focus on interferometers employing laser-cooled neutralatoms. The variety of ways in which atoms with internal states can respond tofields of external perturbations and ‘interfere’ is reflected in the richvariety of atom interferometers that can explore avenues not accessible tooptical interferometers. In particular, I will discuss the operation ofquantum interferometers in a gravitational field, stressing its ability tomeasure gravitational and inertial fields with unprecedented sensitivity. Thisalso leads to some fundamental issues of interpretation in the context ofgravitational redshift and time dilation. I will end with discussion whethergravimetry with quantum interferometers is equivalent to a measurement of thegravitational time dilation.
