Programme

I.3 -- Invited

Date: Friday, 24 November 2017

Time: 13:30 - 14:15

Size-dependent Thermodynamic Properties of Ultra-thin Ferroic Films

Cong Thanh Bach (*), Niem Tu Nguyen, Giang Huong Bach

Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Hanoi, Vietnam

Ultra-thin ferroic (ferromagnetic of ferroelectric) films with few atomic layers show size- dependent thermodynamic properties more distinctly than dozen or hundred nanometer- thick films. The thermodynamic equilibrium theory for the XZ Heisenberg model in the transverse and longitudinal fields, which is generalized of transverse Ising model, is used to describe finite-temperature properties of the ultra-thin ferroic films. We also investigate the size dependence of the order-disorder phase transition using mean field and Gaussian fluctuation approximations. Our analytic calculations reveal that physical properties such as: order parameters, critical transverse field, specific heat, spin reorientation... and the nature of elementary excitation depend on both the film thickness and the transverse-field intensity. Numerical calculation was carried out specific ferroic ultra-thin films for comparison with experimental results. (*) Email: congbt@vnu.edu.vn; congbachthanh@gmail.com

Presenter: Bach Thanh Cong