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Title: High temperature spin dynamics in linear magnetic chains, molecular rings, and segments by nuclear magnetic resonance

We present the room temperature proton nuclear magnetic resonance (NMR) nuclear spin-lattice relaxation rate (NSLR) results in two 1D spin chains: the Heisenberg antiferromagnetic (AFM) Eu(hfac){sub 3}NITEt and the magnetically frustrated Gd(hfac){sub 3}NITEt. The NSLR as a function of external magnetic field can be interpreted very well in terms of high temperature spin dynamics dominated by a long time persistence of the decay of the two-spin correlation function due to the conservation of the total spin value for isotropic Heisenberg chains. The high temperature spin dynamics are also investigated in Heisenberg AFM molecular rings. In both Cr{sub 8} closed ring and in Cr{sub 7}Cd and Cr{sub 8}Zn open rings, i.e., model systems for a finite spin segment, an enhancement of the low frequency spectral density is found consistent with spin diffusion but the high cut-off frequency due to intermolecular anisotropic interactions prevents a detailed analysis of the spin diffusion regime.
Authors:
;  [1] ;  [2] ;  [3] ; ; ;  [4] ; ;  [5] ; ;  [6]
  1. Dipartimento di Fisica, Università degli Studi di Milano and INSTM, Milano (Italy)
  2. (Italy)
  3. Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna (Italy)
  4. Dipartimento di Chimica, Università degli Studi di Firenze and INSTM, Firenze (Italy)
  5. School of Chemistry, The University of Manchester, Manchester (United Kingdom)
  6. Dipartimento di Fisica, Università degli Studi di Pavia and INSTM, Pavia (Italy)
Publication Date:
OSTI Identifier:
22409948
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; ANTIFERROMAGNETIC MATERIALS; ANTIFERROMAGNETISM; ATOMIC FORCE MICROSCOPY; CADMIUM; CHROMIUM; CORRELATION FUNCTIONS; DIFFUSION; HEISENBERG MODEL; MAGNETIC FIELDS; NMR SPECTRA; NUCLEAR MAGNETIC RESONANCE; PROTONS; SPECTRAL DENSITY; SPIN-LATTICE RELAXATION; TEMPERATURE DEPENDENCE