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Linear Magnetic Birefringence and Near Infrared Absorption of K 2 NiF 4
Author(s) -
Kleemann W.,
Pommier J.
Publication year - 1974
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.2220660240
Subject(s) - birefringence , ground state , absorption (acoustics) , raman spectroscopy , debye model , line (geometry) , atmospheric temperature range , infrared , condensed matter physics , materials science , debye , chemistry , analytical chemistry (journal) , atomic physics , nuclear magnetic resonance , optics , physics , thermodynamics , geometry , mathematics , chromatography , composite material
Evidence of 2D magnetic short‐range order has been observed in the linear magnetic birefringence (LMB) of K 2 NiF 4 up to 3T N (≈300 K) in agreement with specific heat and Raman data. Below T N/2 the LMB is proportional to the long‐range order parameter M 2 Both results are explained by magnetostriction due to 2D and 3D Spin–order, respectively. The fine structure of the 3 A 2g → 3 T 2g absorption band at LHeT is discussed. The MCD of the lowest Spin–orbit component τ 3 yields g ‖ = 2.27 ± 0.04 for the ground state. The Debye temperature θ ≈ 335 K is obtained from the temperature dependence of the τ3 line. Only about 5% of the thermal line shift below 0.7 T N is estimated to be due to the decrease of the exchange stabilization of the ground state.