Programme

P.44 -- Poster, VCTP-49

Date: Friday, 2 August 2024

Time: 08:30 - 10:00

Thermodynamic properties of monolayer honeycomb spin lattice

Niem T. Nguyen, Giang H. Bach, Cong T. Bach

Faculty of Physics, VNU University of Science 334 Nguyen Trai, Thanh Xuan, Ha Noi

The transverse Ising model is used in the thermodynamic theory of ferroic materials [1]. The Ising model in longitudinal field is used to investigate the first order magnetization process in bilayer honeycomb spin films [2]. In this research, spin systems with arbitrary spin value S in a single-layer honeycomb spin lattice have been investigated using the functional integral method and the Ising model in longitudinal and transverse fields. An expression for the free energy in the Gaussian approximation consisting of two terms has been obtained: the mean field term and the spin fluctuation term. From this, expressions for the general spin wave spectrum for different magnetic structures (ferromagnetic, antiferromagnetic, and ferrimagnetic) have been obtained. The influence of spin fluctuations on the magnetization process in an external field for a ferromagnetic structure has been examined. [1] Cong T. Bach, Niem T. Nguyen, Giang H. Bach, Thermodynamic properties of ferroics described by the transverse Ising model and their applications for CoNb2O6, J. Magn. Magn. Mater. 483 (2019) 136. [2] Niem T. Nguyen, Giang H. Bach, Thao H. Pham, Huy D. Nguyen, Oanh T.K. Nguyen and Cong T. Bach, Magnetization Process in Bilayer Honeycomb Spin Lattice, Materials Transactions, 64 (2023) 2118.

Presenter: Nguyen Tu Niem