Regular Article

Spin-1/2 Ising–Heisenberg Cairo pentagonal model in the presence of an external magnetic field: effect of Landé g-factors

¹ A.I. Alikhanyan National Science Laboratory, Alikhanian Br. 2, 0036 Yerevan, Armenia
² ICTP, Strada Costiera 11, 34151 Trieste, Italy
³ Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste, Italy
⁴ CNR-IOM DEMOCRITOS Simulation Center and SISSA, Via Bonomea 265, 34136 Trieste, Italy
⁵ CANDLE Synchrotron Research Institute, Acharyan 31, 0040 Yerevan, Armenia
⁶ BLTP, Joint Institute for Nuclear Research, Dubna, Moscow Region 141980, Russia

^a e-mail: arianzad.hamid@yerphi.am

Received: 27 April 2020
Received in final form: 28 July 2020
Accepted: 3 August 2020
Published online: 4 November 2020

Abstract

In the present paper, a study of the magnetic properties of a spin-1/2 Ising–Heisenberg Cairo pentagonal structure is presented. The model has been investigated in [F.C. Rodrigues, S.M. de Souza, O. Rojas, Ann. Phys. 379, 1 (2017)] in the absence of external magnetic field. Here, we consider the effects of an external tunable magnetic field. By using the transfer matrix approach, we investigate the magnetic ground-state phase transition, the low-temperature magnetization process, and how the magnetic field influences the various thermodynamic parameters such as entropy, internal energy and specific heat. It is shown that the model exhibits intermediate magnetization plateaux accompanied by a double-peak in the specific heat curve versus temperature. The position of each magnetization jump is in accordance with the merging and/or separation of the two peaks in the specific heat curve. Considering different g-factors for the nodal Ising spins and spin dimers also results in arising different intermediate plateaux and to remarkable alterations of the thermodynamic properties of the model.