Date of Award
Master of Science
Low-dimensional magnetic materials show novel properties that is not seen in bulk magnets. The weak interactions such as spin-orbit interactions, electron correlation, van der Waals interaction in case magnetic bi-layers, play an important role in determining the properties of the system. Using density functional theory, we computationally investigated two categories of magnetic material- 1: Single Molecular Magnets (SMM) 2: Van der Waals layered Cr-Halide magnets. We used different classes of density functionals to examine the spin ordering and magnetic anisotropy barriers in several single molecule magnets - Mn12, Co4, Ni4, V15. We find that the magnetic anisotropy barrier significantly depends on the choice of the functional and also on the structure. On our second part of the project we perform calculations on bi-layered systems CrBr3and CrI3. To treat the correlated d-orbitals of the Cr3+we perform GGA+U correction in order to capture correct electronic properties of the system. Also, our theoretical calculation suggests that that van-der-Waals (vdW) functionals which is non-local exchange correlation function of vdW-DF represent the vdw interaction between the stack of layers and the generalized gradient approximation (GGA-PBE) are inadequate for the description of vdW interactions. We also report comparative study of the MAE, and magnetic exchange interaction (J) with respect to pressure up to 1GPa.
Received from ProQuest
Md Shamsul Alam
Alam, Md Shamsul, "Density Functional Calculations On Single Molecular (1d) And Van Der Waals Bi -Layered (2d) Magnets." (2020). Open Access Theses & Dissertations. 3078.