A study of long range order in certain two-dimensional frustrated lattices

We have studied the Heisenberg antiferromagnets on two-dimensional frustrated lattices, triangular and kagome lattices using linear spin-wave theory. A collinear ground state ordering is possible if one of the three bonds in each triangular plaquette of the lattice becomes weaker or frustrated. We study spiral order in the Heisenberg model along with Dzyaloshinskii-Moriya (DM) interaction and in the presence of a magnetic field. The quantum corrections to the ground state energy and sublattice magnetization are calculated analytically in the case of triangular lattice with nearesr-neighbour interaction. The corrections depend on the DM interaction strength and the magnetic field. We find that the DM interaction stabilizes the long-range order, reducing the effect of quantum fluctuations. Similar conclusions are reached for the kagome lattice. We work out the linear spin-wave theory at first with only nearest-neighbour (nn) terms for the kagome lattice. We find that the nn interaction is not sufficient to remove the effects of low energy fluctuations. The flat branch in the excitation spectrum becomes dispersive on addition of furthet neighbour interactions. The ground state energy and the excitation spectrum have been obtained for various cases.Comment: 18 pages, 9 figure

Collinear N\'eel-type ordering in partially frustrated lattices

We consider two partially frustrated S = 1/2 antiferromagnetic spin systems on the triangular and pentagonal lattices. In an elementary plaquette of the two lattices, one bond has exchange interaction strength $\alpha$ ($\alpha \leq 1$) whereas all other bonds have exchange interaction strength unity. We show that for $\alpha$ less than a critical value $\alpha_{c}$, collinear N\'eel-type ordering is possible in the ground state. The ground state energy and the excitation spectrum have been determined using linear spin wave theory based on the Holstein-Primakoff transformation.Comment: Four pages, LaTeX, Four postscripts figures, Phys. Rev. B58, 73 (1998

Abstracts of National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020

This book presents the abstracts of the papers presented to the Online National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020 (RDMPMC-2020) held on 26th and 27th August 2020 organized by the Department of Metallurgical and Materials Science in Association with the Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, India. Conference Title: National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020Conference Acronym: RDMPMC-2020Conference Date: 26–27 August 2020Conference Location: Online (Virtual Mode)Conference Organizer: Department of Metallurgical and Materials Engineering, National Institute of Technology JamshedpurCo-organizer: Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, IndiaConference Sponsor: TEQIP-