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The FM/AFM bilayer Bethe lattice with FM or AFM interlayer interactions
Author(s) -
Albayrak Erhan
Publication year - 2009
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.200844204
Subject(s) - antiferromagnetism , spins , condensed matter physics , ferromagnetism , ising model , phase diagram , atomic force microscopy , bilayer , phase transition , ferrimagnetism , lattice (music) , physics , ground state , superlattice , materials science , phase (matter) , chemistry , magnetic field , nanotechnology , quantum mechanics , magnetization , biochemistry , membrane , acoustics
The bilayer Bethe lattice with the Ising spins of the top layer having only ferromagnetic (FM) interactions and the spins of the bottom one having only antiferromagnetic (AFM) interactions were allowed to interact via the interlayer interaction either FM or AFM type. The problem was analyzed by using the exact recursion relations in a pairwise approach for given coordination numbers q = 3, 4 and 6 with equal external magnetic fields acting on the layers. The phase diagrams of the model were obtained on different planes for given system parameters by studying the ground state (GS) phase diagrams and the thermal variations of the order parameters and the response functions, i.e. the susceptibility and the specific heat, in detail. The model with five distinct GS configurations presents only the second‐order phase transition lines, i.e. the lines of the Néel temperatures T N . Two T N 's were obtained for q = 6 in the transition regions from the AFM phases to the FM phases at low temperatures, as a result the T N lines show reentrant behavior for q = 6. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)