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ESR Studies of Cu 2+ in NH 4 Cl Single Crystals between 4.2 and 453 °K. I. Spin‐Hamiltonian Parameters and Lattice Constant for NH 4 Cl
Author(s) -
Pilbrow J. R.,
Spaeth J. M.
Publication year - 1967
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.19670200119
Subject(s) - tetragonal crystal system , hyperfine structure , ground state , lattice constant , atmospheric temperature range , hamiltonian (control theory) , chemistry , condensed matter physics , lattice (music) , atomic physics , crystal structure , crystallography , physics , thermodynamics , diffraction , quantum mechanics , mathematical optimization , mathematics , acoustics
ESR spectra from two different Cu 2+ with [100] tetragonal symmetry were observed in NH 4 Cl single crystals. The spin‐Hamiltonian parameters for both centres were determined in the temperature range 4.2 to 453 °K where NH 4 Cl has the CsCl structure. The g ‐values and hyperfine constants for both centres show a marked anomaly in the vicinity of the λ‐point and significant variations over the whole temperature range. Both centres have essentially a |3 z 2 – r 2 〉 ground state, but with evidence of vibrational admixtures of the | x 2 – y 2 〉 state. In view of possible future calculations of the Cu 2+ spin polarization and radial wave function for the ground state, the lattice parameter of NH 4 Cl and NH 4 Cl:Cu was measured in the temperature range 105 to 453 °K.