Mixed-spin system with supersolid phases: magnetocaloric effect and thermal properties

Abstract

Recently, it has been shown that two dimensional frustrated mixedspin systems with anisotropic exchange interactions display supersolid phases in their ground state phase diagrams even in the absence of long-range interactions. In this paper, using cluster mean field theory, we investigate the effects of thermal fluctuations on the ground state phases of this kind of systems and show that various thermal solids and thermal insulators emerge around the ground state solid and Mott insulating phases. We also study the thermodynamic properties and magnetocaloric effect of these systems and demonstrate that at low temperatures, a large cooling rate is seen in the vicinity of the solid-supersolid, solid-superfluid and Mott insulator-superfluid critical points, with the large accumulation of the entropy and the minimums of the isentropes. Our results show the sign change of the magnetocaloric parameter inside the solids and the Mott insulator, which is a characteristic of ordered phases.

Magnetic phase diagram of CrPS4 and its exchange interaction in contact with NiFe

“…When applying the magnetic field beyond the black dots boundary, the spinflop transition happens. All magnetic moments tend to align along the external field in area B, CrPS 4 is now in a canted antiferromagnetic phase (AF2) , and spin-flip happens to cross the boundary into C area to show the ferromagnetic phase (FM) or full phase [22]. It is worth noting the presence of the paramagnetic phase (PM) when the temperature is high enough to break the magnetic order.…”

Numerical Interchain Mean-Field Theory for the Specific Heat of the Bimetallic Ferromagnetically Coupled Chain Compound MnNi(NO2)4(en)2 (en = Ethylenediamine)

“…Mean-field theory has been used before for this purpose (see, e.g., Refs. [ 78 , 79 , 80 , 81 ]). Indeed, once the self-consistent mean-field solution is known, both the free energy F and the internal energy U are straightforward to compute; from these, one obtains the entropy via Figure A4 presents results of the entropy for our mixed-spin system with (a) and (b).…”

Theoretical analysis of magnetic properties and the magnetocaloric effect using the Blume-Capel model

“…Blume-Emery-Griffiths (BEG) model [54][55][56][57], mixed-spin Ising model [58][59][60][61][62][63] and Blume-Capel (BC) model [64][65][66][67][68][69][70][71][72]. The properties of MCE in the generalized spin-S model were studied by Yüksel and collaborators [73] using the MFT, and by Akinci and collaborators [74] who studied the MCE using the effective-field theory, where they concentrated their studies on continuous phase transitions.…”