Ph.D. THESIS COLLOQUIUM
Presenter Name: Akmal Hossain
Ph.D. Supervisor: Prof. D. D. Sarma
Date & Time : 9th March, 2022 at 4:00 pm through Microsoft Teams
Title: Investigation of strongly correlated paramagnetic state at sub-Kelvin regime for S ≥ 1/2 systems: Role of disorder and dimensionality
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Abstract:
A magnetic system is normally expected to show long range magnetic order at a temperature scale comparable to the interaction strength between the spins on different sites. Such magnetic orderings are helped by an increase in the dimensionality as determined by the spin-spin correlation along the three different directions. However, magnetic frustration, which may appear in some specific geometries of magnetic lattices, can lead to a suppression in the ordering temperature because of the presence of competing spin-spin interactions that cannot be satisfied simultaneously. Another approach to inhibit a system from ordering magnetically is based on introduction of disorder in the magnetic network; usually such disorders promote frozen disordered spin states at low temperatures. In this thesis work, we will be discussing examples of interesting dynamic, correlated paramagnetic states in a few selected materials at the sub-Kelvin regime, suggesting unusual magnetic ground states and opening new possibilities to explore the field of frustrated magnetism aided by disorder and dimensionality.
References:
[1] C. Lacroix, P. Mendels, and F. Mila, Introduction to Frustrated Magnetism: Materials, Experiments, Theory, 164, Springer Science & Business Media, New York (2011)
[2] A. Vasiliev, O. Volkova, E. Zvereva, and M. Markina, npj Quantum Mater. 3, 18 (2018)
[3] J. A. Mydosh, Spin Glasses: An Experimental Introduction, Taylor & Francis (1993)
[4] S. Kundu and A. Hossain et al. Phys. Rev. Lett. 125, 117206 (2020)