Chemical effects at interfaces of Fe/MgO/Fe magnetic tunnel junction. (December 2016)

• Record Type: Journal Article
• Authors: Singh, Jitendra Pal; Kaur, Baljeet; Gautam, Sanjeev; Lim, Weon Cheol; Asokan, Kandasami; Chae, Keun Hwa
• Is Part Of: Superlattices and microstructures. Volume 100(2016)
• Page Start: 560
• Page End: 586
• Publication Date: 2016-12
• Subjects: Chemical effects -- Magnetic tunnel junction -- Interface resonance states -- Ion irradiation; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2016.10.015
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: Present review focuses the investigation carried out in order to understand the interface structure of magnetic tunnel junction (MTJ) by considering Fe/MgO/Fe as prototype structure. Tunneling magnetoresistence (TMR) of MTJ is affected by the spin polarization of ferromagnetic layers. This phenomena is governed by spin dependent tunneling in perfect MTJ. In MTJ with disordered interface, resonance states through interface play an important role. Some important phenomena like perpendicular magnetic anisotropy, spin transfer torques, and electrical switching are also affected by the interface structure. Apart from disorder and lattice mismatch, interface structure is governed by several factors like oxidation, defects, vacancies as well as hybridization among Fe(3 d )-O(2 p ) states. These effects are categorized as 'chemical effects'. Due to these factors, contribution from interface resonance states dominates which reduces TMR and related properties. A discussion for determination of these effects are highlighted using several techniques like X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. Simulation results reveal modification of TMR via chemical effects occuring at interface in these MTJ. Thus tailoring of chemical effects in controlled manner is discussed to understand the interface assisted phenomena in these structures. Modification of the chemical effects is induced by irradiation of swift heavy ions, thereby, providing an opportunity to correlate chemical effects and TMR of MTJ. Graphical abstract: Highlights: Interface structure affects spin dependent tunneling. Chemical effects are dominant at interfaces. These effects can be tailored using swift heavy ion irradiation.