osnaDocs: Magnetic properties and proton spin-lattice relaxation in molecular clusters

Magnetic properties and proton spin-lattice relaxation in molecular clusters

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https://osnadocs.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2006060610

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DC Field	Value	Language
dc.contributor.advisor	Apl. Prof. Dr. Jürgen Schnack.
dc.creator	Allalen, Mohammed
dc.date.accessioned	2010-01-30T14:36:21Z
dc.date.available	2010-01-30T14:36:21Z
dc.date.issued	2006-06-06T14:24:10Z
dc.date.submitted	2006-06-06T14:24:10Z
dc.identifier.uri	https://osnadocs.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2006060610	-
dc.description.abstract	In this work we studied magnetic properties of molecular magnets of the new heteropolyanion {Cu20}, dodecanuclear cluster {Ni12}, and the heterometallic {Cr7M} wheels, in which one of the CrIII ions of Cr8 has been replaced by a Fe, Cu, Zn, Ni, ion with this extra-spin acts as local probe for the spin dynamics.Such systems have been synthesized recently and they are well described using the Heisenberg spin Hamiltonian with a Zeeman term of an applied magnetic field along the z-axis. Using the numerical exact diagonalization method, we have calculated the energy spectrum and the eigenstates for different compounds,and we have used them for reexamining the available experimental susceptibility data to determine the values of exchange parameters.We have studied the thermodynamic properties such magnetization, susceptibility, heat-capacity. At low temperature regions molecular magnets act as individual quantum nanomagnets and can display super-paramagnetic phenomena like macroscopic quantum tunneling, ground state degeneracy, level-crossing. A crucial issue for understanding these phenomena is the coupling between magnetic molecular levels and the environment such as nuclear spins. We have modeled the behavior of the proton spin lattice relaxation rate as a function of applied magnetic field for low temperatures as it is measured in Nuclear Magnetic Resonance (NMR) experiments.	eng
dc.language.iso	eng
dc.subject	Molecular magnetism
dc.subject	Heisenberg model
dc.subject	proton spin lattice relaxation rate.
dc.subject.ddc	530 - Physik	ger
dc.title	Magnetic properties and proton spin-lattice relaxation in molecular clusters	eng
dc.type	Dissertation oder Habilitation [doctoralThesis]	-
thesis.location	Osnabrück	-
thesis.institution	Universität	-
thesis.type	Dissertation [thesis.doctoral]	-
thesis.date	2006-05-03T12:00:00Z	-
elib.elibid	562	-
elib.marc.edt	ulrike.busch	-
elib.dct.accessRights	a	-
elib.dct.created	2006-05-16T13:10:42Z	-
elib.dct.modified	2006-06-06T14:24:10Z	-
dc.contributor.referee	Apl. Prof. Dr. Manfred Neumann
dc.subject.dnb	29 - Physik, Astronomie	ger
dc.subject.pacs	75.10.-b - General theory and models of magnetic ordering	eng
dc.subject.pacs	75.10.Jm - Quantized spin models	eng
dc.subject.pacs	75.50.Ee - Antiferromagnetics	eng
vCard.ORG	FB4	ger
Appears in Collections:	FB06 - E-Dissertationen

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