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Application of nonlinear EPR and NMR responses on spin systems in structure and relaxation structures

Conference:

Abstract

Full text: In this work results of investigation of paramagnetic systems (irradiated polymers and crystals, plastic-deformed metals, systems with strong exchange interaction, etc.) by methods of nonlinear relaxation spectroscopy (NRS) are presented. The NRS theoretical grounds were developed in the earlier works. Later the technique was applied successfully to relaxation studies and when analyzing magnetic resonance complicated overlapping spectra. As in course of polymer system irradiation, basically, several type of paramagnetic defects are formed with close values of the g factors, these materials can be used to exemplify NRS capabilities. In this work we use samples of irradiated PMMA copolymers. Analysis of the PMMA spectra shows that several types of paramagnetic defects strongly differing in the spin-lattice relaxation times are formed in irradiated PMMA-based polymer composites. It is found that degradation of the composite physical and engineering characteristics is caused, mainly, by radiation-induced disintegration of macromolecules, following the chain reaction, which can be revealed by occurring lattice radical states. Another portion of work is devoted to NRS application to deterring influence of structural defects (impurity, dislocation, etc.) on variation in times of nuclear spin-lattice relaxation in metal systems. At this stage we managed, for the first time, to separate the  More>>
Authors:
Polyakov, A I; Ryabikin, Yu A; Bitenbaev, M M [1] 
  1. Inst. of Physics and Technology, Almaty (Kazakhstan)
Publication Date:
Jul 01, 2004
Product Type:
Conference
Resource Relation:
Conference: 8. International conference 'Solid State Physics', 8.Mezhdunarodnaya konferentsiya 'Fizika Tverdogo Tela', Almaty (Kazakhstan), 23-26 Aug 2004; Other Information: 4 refs; Related Information: In: Abstracts of 8. International conference 'Solid State Physics', Tezisy 8.Mezhdunarodnoj konferentsii 'Fizika Tverdogo Tela', 473 pages.
Subject:
36 MATERIALS SCIENCE; DIPOLES; ELECTRON SPIN RESONANCE; IMPURITIES; NUCLEAR MAGNETIC RESONANCE; PMMA; SPIN; SPIN-LATTICE RELAXATION
OSTI ID:
20631714
Research Organizations:
Inst. Yadernoj Fiziki Natsional'nogo Yadernogoj Tsentra Respubliki Kazakhstan, Almaty (Kazakhstan)
Country of Origin:
Kazakstan (Kazakhstan)
Language:
English
Other Identifying Numbers:
Other: ISBN 9965-675-16-3; TRN: KZ0502973074607
Submitting Site:
INIS
Size:
page(s) 82-83
Announcement Date:
Oct 29, 2005

Conference:

Citation Formats

Polyakov, A I, Ryabikin, Yu A, and Bitenbaev, M M. Application of nonlinear EPR and NMR responses on spin systems in structure and relaxation structures. Kazakstan (Kazakhstan): N. p., 2004. Web.
Polyakov, A I, Ryabikin, Yu A, & Bitenbaev, M M. Application of nonlinear EPR and NMR responses on spin systems in structure and relaxation structures. Kazakstan (Kazakhstan).
Polyakov, A I, Ryabikin, Yu A, and Bitenbaev, M M. 2004. "Application of nonlinear EPR and NMR responses on spin systems in structure and relaxation structures." Kazakstan (Kazakhstan).
@misc{etde_20631714,
title = {Application of nonlinear EPR and NMR responses on spin systems in structure and relaxation structures}
author = {Polyakov, A I, Ryabikin, Yu A, and Bitenbaev, M M}
abstractNote = {Full text: In this work results of investigation of paramagnetic systems (irradiated polymers and crystals, plastic-deformed metals, systems with strong exchange interaction, etc.) by methods of nonlinear relaxation spectroscopy (NRS) are presented. The NRS theoretical grounds were developed in the earlier works. Later the technique was applied successfully to relaxation studies and when analyzing magnetic resonance complicated overlapping spectra. As in course of polymer system irradiation, basically, several type of paramagnetic defects are formed with close values of the g factors, these materials can be used to exemplify NRS capabilities. In this work we use samples of irradiated PMMA copolymers. Analysis of the PMMA spectra shows that several types of paramagnetic defects strongly differing in the spin-lattice relaxation times are formed in irradiated PMMA-based polymer composites. It is found that degradation of the composite physical and engineering characteristics is caused, mainly, by radiation-induced disintegration of macromolecules, following the chain reaction, which can be revealed by occurring lattice radical states. Another portion of work is devoted to NRS application to deterring influence of structural defects (impurity, dislocation, etc.) on variation in times of nuclear spin-lattice relaxation in metal systems. At this stage we managed, for the first time, to separate the distribution functions for spin-lattice relaxation (T{sub l}) and relaxation of nuclear spin dipole-dipole interaction (T{sub d}). It is shown that one can assess an extent of crystal defect by the dependence of T{sub d}=f(c). Also in this work the NRS methods are applied to analyze EPR spectra of polycrystalline solid systems where exchange interaction is strong. It is shown that these systems, as a rule, contain a complete set of spin assemblies having different relaxation times, and the spin assembly distribution over the relaxation time depends on the defect number and type in solid systems under study. In this respect, the current idea on homogeneous spin systems with strong exchange interaction, seemingly, should be revised.}
place = {Kazakstan (Kazakhstan)}
year = {2004}
month = {Jul}
}