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Study of Crossover Behaviour in Layered Antiferrormagnets
Author(s) -
Singh Ravi P.
Publication year - 1993
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.2221790119
Subject(s) - crossover , condensed matter physics , anisotropy , magnetization , random phase approximation , spin wave , physics , heisenberg model , phase (matter) , spin (aerodynamics) , quantum mechanics , ferromagnetism , magnetic field , thermodynamics , computer science , artificial intelligence
The dimensional crossover from 3D to quasi‐2D character in magnetic properties of layered antiferromagnets such as La 2 CuO 4 (2‐1‐4) is studied. The theoretical framework is based on an anisotropic Heisenberg model. Random phase approximation (RPA) is used to obtain a self‐consistent expression for the magnetization. It is shown that under specific approximations on this theory, free‐spin‐wave (FSW) results can be obtained. With the help of this self‐consistent theory it is shown that the crossover occurs as the value of dimensional anisotropy parameter ( J c / J ab ) changes from about 10 −3 . Numerical results for the sublattice magnetization are obtained depicting this crossover and compared with free‐spin‐wave results. The results obtained from this self‐consistent calculations are in excellent agreement with the experimental results obtained for 2‐1‐4 materials.