Prediction of the existence of an intermediate phase in the antiferromagnetic J1-J2system on the face-centered cubic lattice

Abstract

The structure o f the phase diagram of the antiferromagnetic Ising model with the presence of the nearest-neighbor and next-nearest-neighbor interactions on the face-centered cubic lattice is investigated in detail in the framework of the recursive lattice approximation. The existence of an additional well-defined intermediate phase is predicted that separates two standard antiferromagnetic phases of the model. This new phase is realized in the form of a narrow strip in the phase diagram but can be observed for a rather large interval of the frustration parameter of the model. Moreover, analyzing the sublattice magnetization properties of the model, it is shown that transitions between all model phases have the second-order nature. All predicted series of successive phase transitions of the model caused by the presence of the intermediate phase are studied.