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State Equation of the Ising Model in the Ladder Approximation
Author(s) -
Sadreev A. F.
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.2220630133
Subject(s) - ising model , magnetization , magnetic field , condensed matter physics , equation of state , physics , square lattice ising model , field (mathematics) , diagram , state (computer science) , mathematical physics , mathematics , quantum mechanics , statistics , algorithm , pure mathematics
The three‐dimensional Ising model for the case S = ½ in an external magnetic field is considered by the diagram expansion of the Green temperature function. The state equation of the Ising model is proposed in the ladder approximation. The calculation of the state equation is given as magnetization curves for the temperature region T ⪆ T e and for magnetic fields H = 18 and 5 kOe. Also the Tyablikov equation is solved for the same temperatures and magnetic fields. The comparison shows a better agreement of the ladder approximation with the experimental data than the molecular field approximation or the Tyablikov equation.