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

Journal Article · Thu May 07 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4916022· OSTI ID:22409948

Adelnia, Fatemeh; Lascialfari, Alessandro ^[1]; Mariani, Manuel ^[2]; Ammannato, Luca; Caneschi, Andrea; Rovai, Donella ^[3]; Winpenny, Richard; Timco, Grigore ^[4]; Corti, Maurizio; Borsa, Ferdinando ^[5]

---

1. Dipartimento di Fisica, Università degli Studi di Milano and INSTM, Milano (Italy)
2. Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna (Italy)
3. Dipartimento di Chimica, Università degli Studi di Firenze and INSTM, Firenze (Italy)
4. School of Chemistry, The University of Manchester, Manchester (United Kingdom)
5. Dipartimento di Fisica, Università degli Studi di Pavia and INSTM, Pavia (Italy)

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.

• OSTI ID: 22409948
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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