Dynamical mean-field theoretical approach to explore the temperature-dependent magnetization in Ta-doped TiO2

International Symposium on Current Progress in Functional Materials

Majidi, M.A.^1 ; Umar, A.S.^1 ; Rusydi, A.^2,3

Department of Physics, Faculty of Mathematics, Natural Sciences Universitas Indonesia, Kampus UI Depok, Depok

16424, Indonesia^1

NUSNNI-NanoCore, Department of Physics, Faculty of Science, National University of Singapore, Singapore

117576, Singapore^2

Singapore Synchrotron Light Source, National University of Singapore, Singapore

117603, Singapore^3

关键词: Dynamical mean-field theory;    Ferromagnetic orderings;    Local magnetic moments;    Ruderman-Kittel-Kasuya-Yosida;    Spintronic applications;    Temperature dependence;    Temperature-dependent magnetizations;    Theoretical approach;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/188/1/012061/pdf
DOI  :  10.1088/1757-899X/188/1/012061

来源: IOP

【 摘 要 】

TiO2has, in recent years, become a hot subject as it holds a promise for spintronic application. Recent experimental study on anatase Ti1-xTaxO2(x ∼ 0.05) thin films shows that the system changes from non-magnetic to ferromagnetic due to Ti vacancies that are formed when a small percentage of Ti atoms are substituted by Ta. Motivated by those results that reveal the ferromagnetic phase at room temperature, we conduct a theoretical study on the temperature-dependent magnetization and the Currie temperature of that system. We hypothesize that when several Ti vacancies are formed in the system, each of them induces a local magnetic moment, then such moments couple each other through Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, forming a ferromagnetic order. To study the temperature dependence of the magnetization and predict the Curie temperature, we construct a tight-binding based Hamiltonian for this system and use the method of dynamical mean-field theory to perform calculations for various temperatures. Our work is still preliminary. The model and method may need further improvement to be consistent with known existing facts. We present our preliminary results to show how the present model works.