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EPR of a Gd 3+ ‐Doped NH 4 Pr(SO 4 ) 2 · 4 H 2 O Single Crystal. Study of Phase Transition and Superposition Model Calculation of Zero‐Field Splitting Parameters
Author(s) -
Misra S. K.,
Sun Jiansheng
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.2221620123
Subject(s) - electron paramagnetic resonance , spectral line , crystal (programming language) , ion , doping , atmospheric temperature range , single crystal , phase transition , chemistry , crystallography , atomic physics , materials science , analytical chemistry (journal) , physics , nuclear magnetic resonance , condensed matter physics , chromatography , computer science , programming language , organic chemistry , astronomy , meteorology
Abstract X‐band EPR spectra of a single crystal of Gd ++ ‐doped NH 4 Pr (SO 4 ) 2 · 4 H 2 O (APST) are recorded in the temperature range 4.2 to 410 K. The angular variation of the EPR line positions indicates the presence of two magnetically‐inequivalent Gd 3+ ions. The orientations of their principal axes are determined. The Gd 3+ spin‐Hamiltonian parameters are evaluated using a rigorous least‐squares‐fitting procedure. The superposition model is applied to calculate the values of the zero‐field splitting parameters b 2 0 , b 4 0of Gd 3+ , and those of the intrinsic parameters b 2 and b 4 . The temperature variation of the EPR spectra reveals the occurrences of two first‐order phase transitions in APST crystal at 266 and 155K.