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EPR of a VO 2+ ‐Doped Fe(NH 4 ) 2 (SO 4 ) 2 · 6H 2 O Single Crystal. VO 2 Fe 2+ Exchange Interaction and Spin–Lattice Relaxation Time of Host Fe 2+ Ions
Author(s) -
Misra Sushil K.,
Sun Jiansheng,
Orhun U.
Publication year - 1990
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.2221620232
Subject(s) - electron paramagnetic resonance , ion , crystallography , chemistry , impurity , single crystal , crystal structure , analytical chemistry (journal) , doping , hyperfine structure , nuclear magnetic resonance , materials science , atomic physics , condensed matter physics , physics , organic chemistry , chromatography
X‐band (≈9.5 GHz) electron paramagnetic resonance (EPR) studies of the VO 2+ ion are carried out on a single crystal of the Tutton salt Fe(NH 4 ) 2 (SO 4 ) 2 · 6H 2 O (FASH) at 295, 80, and 4.2 K. The data indicate two physically‐equivalent VO 2+ sites in the unit cell, each consisting of three magneticallyinequivalent VO 2+ ions. The principal values and direction cosines of the principal axes of the g 2 and A 2 tensors are evaluated, using a least‐squares‐fitting program. An impurity [VO(H 2 O) 5 ] 2+ complex model of the vanadyl ion is found to explain the data well. The V 4+ O 2− bond directions for the VO 2+ ions are deduced. The VO 2+ Fe 2+ exchange‐interaction constant in FASH is estimated. The host‐ion (Fe 2+ ) spin‐lattice relaxation time is estimated from VO 2+ EPR linewidth.