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Lattice Parameters, Energy Gaps, and Magnetic Properties of the Cd x Hg y Mn z Te Alloy System
Author(s) -
Manhas S.,
Khulbe K. C.,
Beckett D. J. S.,
Lamarche G.,
Woolley J. C.
Publication year - 1987
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.2221430130
Subject(s) - curie temperature , analytical chemistry (journal) , crystallite , superexchange , atmospheric temperature range , alloy , lattice constant , debye model , condensed matter physics , zinc , materials science , solid solution , magnetic susceptibility , crystallography , chemistry , ferromagnetism , thermodynamics , physics , metallurgy , diffraction , optics , chromatography
Polycrystalline samples of Cd x Hg y Mn z Te alloys ( x + y + z = 1) are prepared by the standard melt and anneal technique. Debye‐Scherrer powder X‐ray photographs are used to determine equilibrium conditions in the alloys, to delineate the range of single phase solid solution and to determine values of zinc blende lattice parameter a . It is found that in the zinc blende field the variation of a with composition can be written as a = (0.6481 – 0.0019 y – 0.0144 z ) nm. Optical absorption measurements are made to give room temperature values of energy gap E g for the single phase alloys and it is found that to a good approximation the composition variation of E g is given by E g = (1.46 – 1.62 y + 1.33 z ) eV. Measurements of magnetic susceptibility in the temperature range 4 to 250 K are made to give values of T g , the spin‐glass transition temperature, and θ, the Curie‐Weiss temperature. Analysis of these data shows that for samples with E g > 1.5 eV, the results are well explained by the superexchange mechanism previously used in the analysis of the Cd x Hg y Mn z Te etc. results, but that for the cases with E g ≦ 1.5 eV a Bloembergen‐Rowland type of interaction needs to be included in order to explain the experimental values of T g and θ.