# Phase diagrams of spin-1 Ising model with bilinear and quadrupolar interactions under magnetic field. Two-particle cluster approximation

## TL;DR

This paper studies the phase diagrams of a spin-1 Ising model with bilinear and quadrupolar interactions under magnetic field using a two-particle cluster approximation, revealing complex critical phenomena.

## Contribution

It introduces a detailed analysis of phase transitions and critical points in the spin-1 Ising model with quadrupolar interactions under magnetic field using a two-particle cluster approach.

## Key findings

- Existence of triple points in phase diagrams.
- Presence of three types of critical points.
- Phase transition between quadrupolar and paramagnetic phases.

## Abstract

The spin-1 Ising model with bilinear and quadrupolar short-range interactions under magnetic field is investigated within the two-particle cluster approximation. It is shown that for those values of the quadrupolar interaction when at zero magnetic field the system undergoes a temperature phase transition between quadrupolar and paramagnetic phases, a triple point may exist in the temperature vs magnetic field phase diagrams, necessarily along with a critical point. It is also shown that the critical points in the temperature vs magnetic field phase diagrams of the investigated model can be of three types.