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      Magnetism of Amorphous and Nano-Crystallized Dc-Sputter-Deposited MgO Thin Films

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          Abstract

          We report a systematic study of room-temperature ferromagnetism (RTFM) in pristine MgO thin films in their amorphous and nano-crystalline states. The as deposited dc-sputtered films of pristine MgO on Si substrates using a metallic Mg target in an O 2 containing working gas atmosphere of (N 2 + O 2) are found to be X-ray amorphous. All these films obtained with oxygen partial pressure (P O2) ~10% to 80% while maintaining the same total pressure of the working gas are found to be ferromagnetic at room temperature. The room temperature saturation magnetization (M S) value of 2.68 emu/cm 3 obtained for the MgO film deposited in P O2 of 10% increases to 9.62 emu/cm 3 for film deposited at P O2 of 40%. However, the M S values decrease steadily for further increase of oxygen partial pressure during deposition. On thermal annealing at temperatures in the range 600 to 800 °C, the films become nanocrystalline and as the crystallite size grows with longer annealing times and higher temperature, M S decreases. Our study clearly points out that it is possible to tailor the magnetic properties of thin films of MgO. The room temperature ferromagnetism in MgO films is attributed to the presence of Mg cation vacancies.

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          Most cited references29

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          A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction.

          Magnetic tunnel junctions (MTJs) with ferromagnetic electrodes possessing a perpendicular magnetic easy axis are of great interest as they have a potential for realizing next-generation high-density non-volatile memory and logic chips with high thermal stability and low critical current for current-induced magnetization switching. To attain perpendicular anisotropy, a number of material systems have been explored as electrodes, which include rare-earth/transition-metal alloys, L1(0)-ordered (Co, Fe)-Pt alloys and Co/(Pd, Pt) multilayers. However, none of them so far satisfy high thermal stability at reduced dimension, low-current current-induced magnetization switching and high tunnel magnetoresistance ratio all at the same time. Here, we use interfacial perpendicular anisotropy between the ferromagnetic electrodes and the tunnel barrier of the MTJ by employing the material combination of CoFeB-MgO, a system widely adopted to produce a giant tunnel magnetoresistance ratio in MTJs with in-plane anisotropy. This approach requires no material other than those used in conventional in-plane-anisotropy MTJs. The perpendicular MTJs consisting of Ta/CoFeB/MgO/CoFeB/Ta show a high tunnel magnetoresistance ratio, over 120%, high thermal stability at dimension as low as 40 nm diameter and a low switching current of 49 microA.
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            Oxide surfaces and metal/oxide interfaces studied by grazing incidence X-ray scattering

            G. Renaud (1998)
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              • Record: found
              • Abstract: not found
              • Article: not found

              Electronic Structure of F and V Centers on the MgO Surface

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                Author and article information

                Journal
                Nanomaterials (Basel)
                Nanomaterials (Basel)
                nanomaterials
                Nanomaterials
                MDPI
                2079-4991
                07 August 2013
                September 2013
                : 3
                : 3
                : 486-497
                Affiliations
                [1 ]Department of Materials Science, Tmfy-MSE, The Royal Institute of Technology, Stockholm SE100 44, Sweden; E-Mails: skm@ 123456kth.se (S.K.M.); fanjincheng2006@ 123456yahoo.com.cn (J.F.); biswas.anis@ 123456gmail.com (A.B.); lyuba@ 123456kth.se (L.B.)
                [2 ]Department of Physics, Amrita Vishwa Vidyapeetham University, Amritapuri Campus, Kollam, Kerala 690525, India; E-Mail: kssreelatha@ 123456yahoo.com
                [3 ]School of Materials and Engineering, Anhui University of Technology, Maanshan 243002, China
                [4 ]Department of Physics, University of South Florida, Tampa, FL 33620, USA
                [5 ]Department of Physics, Government College, Kottayam, Kerala 686013, India
                Author notes
                [* ]Author to whom correspondence should be addressed; E-Mail: rao@ 123456kth.se ; Tel./Fax: +46-0-8790-7771.
                Article
                nanomaterials-03-00486
                10.3390/nano3030486
                5304652
                28348346
                0629e779-31c3-4d96-b2de-2d165f4a4fee
                © 2013 by the authors; licensee MDPI, Basel, Switzerland.

                This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license ( http://creativecommons.org/licenses/by/3.0/).

                History
                : 13 June 2013
                : 20 July 2013
                : 26 July 2013
                Categories
                Article

                room temperature ferromagnetism,mg vacancy,magnetron sputtering,o2 content,annealing

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