Magnetic Properties of Fe/Topological Insulator/Fe Multilayer Films and Nano-columns

Abstract

Tri-layer thin films of Ferromagnet (FM)/ Topological Insulator (TI) IFerromagnet (FM) were synthesized using magnetron DC/ RF sputtering with Bi2Te3 and Bi2Se3 topological insulators as middle buffer layers. The multi-layered samples thus produced was studied using in-house built magneto-optic Kerr effect (MOKE) instrument, vibrating sample magnetometer (VSM), torque magnetometer (TMM), atomic and magnetic force microscopy (AFM / MFM), and ferromagnetic resonance (FMR). This system, that is FM/Insulator/FM on MgO (100) substrates, is a tunnel magneto resistance (TMR) structure often used in magnetic tunnel junction (MTJ) devices. The Fe layer and MgO substrate makes the Fe film act like a free standing Fe monolayer weak interaction between the Fe layer and MgO substrate makes the Fe film act like a free-standing layer, with enhanced magnetic moment [1], [2]. TMR effect is a method by which MTJs are used in developing magneto-resistive random access memory (MRAM), magnetic sensors, and novel logic devices. The main purpose behind this research is to measure the magnetic symmetry of Fe/TI/Fe structure and compare and contrast with the magnetic symmetry of multilayer films and nano-columns. In this presentation, we will present results from MOKE, VSM, TMM, AFM/MFM and FMR studies of Fe/TI/Fe.