Perpendicular magnetic anisotropy in garnet-type ferromagnetic insulators used for inducing T-symmetry break in topological insulators

• Applicant: Dr. Andy Quindeau
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2016 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 310372030

I want to experimentally explore the physical properties and limitations of garnet thin films. Characteristics like magnetic coercivity, anisotropy and remanent magnetization will be quantified and discussed. I plan to conclude how these properties relate to the thin film growth conditions, stoichiometry, film thickness and crystal structure. Furthermore, I want to experimentally demonstrate proximity-induced magnetism with out-of-plane orientation in topological insulators.The primary objective of this project is to reproducibly create and controll the ferromagnetic garnet thin film Tm3Fe5O12 (TmIG) via pulsed laser deposition (PLD) with controllable perpendicular magnetic anisotropy (PMA) in respect to its coercivity and magnetization. Systematic trends of measured magnetic properties will be correlated to the stoichiometric and crystallographic properties. The secondary objective would include a broader study of different types of rare-earth garnets. Potential substituent materials are cerium, with its high magnetostriction (and magnetooptical activity), dysprosium, already used in liquid phase epitaxy garnet films to promote PMA, and dilution of the Fe with Al or Ga to reduce the magnetization and therefore the in-plane anisotropy which will be realized using self made PLD targets of the respective stoichiometry. Finally, by subsequent growth of topological insulators (TI), the existence of possible induced magnetism (lifting of the degeneracy) into the surface TI states will be experimentally investigated.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Dr. Caroline A. Ross