TY - JOUR AU - Kozlovskii, M. P. AU - Pylyuk, I. V. PY - 2019/01/19 Y2 - 2024/03/28 TI - Analytical Description of the Critical Behavior of a Three-Dimensional Uniaxial Magnet in an External Field by Singling Out a Reference System JF - Ukrainian Journal of Physics JA - Ukr. J. Phys. VL - 60 IS - 4 SE - General problems of theoretical physics DO - 10.15407/ujpe60.04.0362 UR - https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2019251 SP - 362 AB - <p>The critical behavior of systems belonging to the universality class of the three-dimensional Ising model has been studied theoretically. A three-dimensional Ising-like system with exponentially decreasing interaction potential and in the presence of a homogeneous external field was considered in the framework of the collective variables method. A specific feature in the calculation of the partition function and the free energy of a uniaxial magnet consists in singling out a reference system. The role of the latter is played by the molecular-field Hamiltonian. A method to describe the critical behavior with the use of a singled out reference system is developed on the basis of a non-Gaussian (quartic) distribution of order-parameter fluctuations (the p4 model).</p> ER -