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Electron Spin Resonance Study of Fe + Centers in NaCl:Fe ++ and Motion of the Associated Vacancies
Author(s) -
Yang B. R.,
Bouwen A.,
Schoemaker D.
Publication year - 1985
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221270227
Subject(s) - vacancy defect , orthorhombic crystal system , electron paramagnetic resonance , crystallography , irradiation , chemistry , crystal (programming language) , k nearest neighbors algorithm , resonance (particle physics) , electron , spectral line , spin (aerodynamics) , atomic physics , crystal structure , materials science , nuclear magnetic resonance , physics , nuclear physics , artificial intelligence , computer science , thermodynamics , astronomy , programming language
X‐irradiation at 77 K of a NaCl:Fe ++ crystal produces orthorhombic and axial Fe + ESR spectra of comparable intensities. The corresponding Fe + (ortho) and Fe + (tetra) centers are identified with, respectively, a substitutional Fe + perturbed by a nearest and a next nearest cation vacancy. At 170 K the cation vacancy of Fe + (ortho) jumps to the next nearest neighbour position enhancing the Fe + (tetra) intensity. Above 215 K the vacancy moves away completely and the unperturbed Fe + (cubic) is formed. It is concluded from this study that before X‐irradiation Fe ++ perturbed by either nearest or next nearest cation vacancies occur in roughly comparable amounts and that the activation energy for cation vacancy motion in NaCl is 0.72 eV.