Programme

P.32 -- Posters, VCTP-51

Date: Tuesday, 4 August 2026

Time: 09:30 - 10:30

Magnetic and transport properties of bilayer honeycomb lattice: Magnetization processes, magneto-caloric effect, and tunneling magneto-conductivity in CrI₃ thin films

Phong H. Nguyen(1), Cong T. Bach(1), Huy D. Nguyen(1), Hoai T.L. Nguyen(2), Hanh H. Mai(3), Duy D. Quang(4), Trung K. Giang(1), Niem T. Nguyen(1) and Giang H. Bach(1,*)

(1) Faculty of Physics, University of Science, Vietnam National University, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam (2) Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Hanoi, Vietnam (3) Faculty of Electronics and Telecommunications, University of Engineering and Technology, Vietnam National University, 144 Xuan Thuy, Hanoi, Vietnam (4) Faculty of Advanced Technology and Engineering, Vietnam-Japan University, Vietnam National University, Hanoi, Luu Huu Phuoc Street, My Dinh 1, Hanoi, Viet Nam

We investigate the magnetic, thermodynamic, magneto-caloric, and transport properties of a bilayer honeycomb spin lattice using both mean field theory and replica-exchange Monte Carlo simulations. In the absence of an external magnetic field, the bilayer system exhibits inter-layer antiferromagnetic (AF) ordering below the Néel temperature, which decreases with reducing inter-layer AF exchange coupling. Under an applied magnetic field, a field-driven first-order magnetization process (FOMP) is observed, characterized by a step-like magnetization curve and an abrupt transition to a fully polarized state at a critical field. The critical field is found to scale linearly with the inter-layer coupling strength, highlighting the key role of inter-layer magnetic interactions in determining the magnetic response. The thermodynamic behavior is further analyzed through the temperature dependence of magnetization, susceptibility, and specific heat. The magnetic entropy change exhibits a distinctive double-peak structure with opposite signs, arising from the competition between AF inter-layer and ferromagnetic intra-layer interactions. This behavior reveals a complex magneto-caloric response associated with field-induced magnetic phase transitions. In addition, the field dependence of the tunneling magneto-conductivity is calculated and shows good agreement with available experimental observations in bilayer CrI₃ thin films. The results clarify the microscopic origin of FOMPs and their direct connection to tunneling magneto-transport phenomena in layered van der Waals magnets.

Presenter: Bach Huong Giang