Magnetic, Electronic Structure And Interface Study Of Fe/MgO/Fe Multilayer

Jitendra Pal Singh^1,6*, Sanjeev Gautam², Braj Bhusan Singh³, Sujeet Chaudhary³, D. Kabiraj¹, D. Kanjilal¹, K. H. Chae², R. Kotnala⁴, Jenn-Min Lee⁵, Jin-Ming Chen⁵, K. Asokan^1*

¹Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India

²Advanced Analysis Centre, Korea Institute of Science and Technology, Seoul 136-791, S. Korea

³Department of Physics, Indian Institute of Technology, New Delhi 110 016, India

⁴National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India

⁵National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan

⁶Department of Applied Physics, Krishna Engineering College, Ghaziabad, Uttar Pradesh 201007, India

Adv. Mater. Lett., 2014, 5 (7), pp 372-377

DOI: 10.5185/amlett.2013.105560

Publication Date (Web): Apr 27, 2014

E-mail: jitendra_singh2029@rediffmail.com, asokaniuac@gmail.com

Full Article

Abstract

MgO based magnetic tunnel junctions (MTJs) exhibit high tunneling magnetoresistance (TMR) and have potential applications in magnetic random access memories. This study addresses the role of interface in the Fe/MgO/Fe based MTJs. For present investigation, Fe/MgO/Fe multilayer stack on Si substrates is grown by electron beam evaporation method and has been investigated for structural, magnetic and electronic properties. All the layers in the stack were of polycrystalline in nature as evidenced from X-ray diffraction studies, and the magnetic measurements show the attributes perpendicular magnetic anisotropy. Results from near edge X-ray absorption spectra at Fe L-edges measured by total electron yield mode and X-ray reflectometry indicate the formation of FeOx at the Fe/MgO interface. These are associated with hybridization of Fe (3d)-O(2p) levels at Fe/MgO interface in the stack and thickness of layers in the stacks. Absence of magnetic de-coupling between top and bottom ferromagnetic layers has been attributed to interface roughness and oxidation at Fe/MgO interface. This study highlights the role of interface and oxidation that need to be considered for improving the TMR for devices.