Modelling magnetic anisotropy of single-chain magnets in vertical bar d/J vertical bar >= 1 regime

Haldar, Sumit and Raghunathan, Rajamani and Sutter, Jean-Pascal and Ramasesha, S (2017) Modelling magnetic anisotropy of single-chain magnets in vertical bar d/J vertical bar >= 1 regime. In: MOLECULAR PHYSICS, 115 (21-22,). pp. 2849-2859.

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Abstract

Single-molecule magnets (SMMs) with single-ion anisotropies comparable to exchange interactions J between spins have recently been synthesised. Here, we provide theoretical insights into the magnetism of such systems. We study spin chains with site-spins, s = 1, 3/2 and 2 and strength of on-site anisotropy comparable to the exchange constants between the spins. We find that large on-site anisotropies lead to crossing of the states with different M-S values in the same spin manifold to which they belong in the absence of anisotropy. When on-site anisotropy is increased further, we also find that the M-S states of the higher energy spin states descend below the M-S states of the ground spin manifold. Giant spin in this limit is no longer conserved and describing the axial and rhombic anisotropies of the molecule, D-M and E-M, respectively, is not possible. However, the giant spin of the low-lying large M-S states is very nearly an integer and, using this spin value, it is possible to construct an effective spin-Hamiltonian and compute the molecular magnetic anisotropy constants D-M and E-M. We report effect of finite sizes, rotations of site anisotropies and chain dimerisation on the effective anisotropy of the spin chains.

Item Type:	Journal Article
Publication:	MOLECULAR PHYSICS
Additional Information:	Copy right for this article belongs to the TAYLOR & FRANCIS LTD, 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	01 Dec 2017 06:48
Last Modified:	01 Dec 2017 06:48
URI:	http://eprints.iisc.ac.in/id/eprint/58373

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