Magnetic and magnetocaloric properties of the exactly solvable mixed-spin Ising model on a decorated triangular lattice in a magnetic field

TL;DR

This paper provides an exact analysis of the magnetic and magnetocaloric properties of a mixed-spin Ising model on a decorated triangular lattice, revealing phenomena like inverse and conventional magnetocaloric effects near zero temperature.

Contribution

It presents an exact solution for the model's ground state, magnetization, critical behavior, and entropy change, highlighting the presence of magnetocaloric effects related to phase transitions and spin frustration.

Findings

Inverse and conventional magnetocaloric effects occur near zero temperature.

Inverse effect appears near discontinuous phase transitions and crossings.

Conventional effect occurs in paramagnetic phases due to spin frustration.

Abstract

The ground state, zero-temperature magnetization process, critical behaviour and isothermal entropy change of the mixed-spin Ising model on a decorated triangular lattice in a magnetic field are exactly studied after performing the generalized decoration-iteration mapping transformation. It is shown that both the inverse and conventional magnetocaloric effect can be found near the absolute zero temperature. The former phenomenon can be found in a vicinity of the discontinuous phase transitions and their crossing, while the latter one occurs in some paramagnetic phases due to a spin frustration to be present at zero magnetic field. The inverse magnetocaloric effect can also be detected slightly above continuous phase transitions following the power-law dependence $|-\Delta{\cal S}_{iso}^{min}|\propto h^n$, where $n$ depends basically on the ground-state spin ordering.