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1、. Besides the CoCrPt-SiO2, other, L10 CoPt and FePt granular film, coupled granular/continuous film , and percolated perpendicular media. Meanwhile, the CoPt/AlN interfaces were flattened as we increased theMagnetic reversal mechanism in CoPt/AlN multilayer filmwith strong perpendicular magnetic ani
2、sotropy#51015Yu Youxing1, Shi Ji2, Nakamura Yoshio2*(1. School of Materials Science and Engineering, Beihang University, Beijing 100191, China;2. Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1,Oh-okayama, Meguro-ku, Tokyo 152-8552, Japan)Abstract: Magnetic rever
3、sal mechanism in highly perpendicular anisotropic CoPt/AlN multilayer hasbeen studied in the present work. The Sub/AlN(5 nm)/CoPt(2 nm)/AlN(5 nm) 5 nano multilayer filmshows a strong perpendicular magnetic anisotropy energy of 6.7106 erg/cm3, which was revealed tooriginate from the magnetoelastic an
4、isotropy and magnetic interface anisotropy in our previous work.In this work, the angle-dependent magnetic hysteresis loops of the nano layered film were measured byapplying a magnetic field along different directions with respect to the film normal. The resultsdemonstrate that the magnetic reversal
5、 of such highly perpendicular magnetic anisotropic layered filmis occurred by the reversible magnetization rotation and the irreversible displacement of domain walls.The internal stress related coercive field is discussed by using the Kondorsky and Kersten model.Key words: Materials physics and chem
6、istry; Magnetic reversal mechanism; Perpendicular magneticanisotropy; CoPt/AlN multilayer200 IntroductionMagnetic thin films with perpendicular anisotropy are easily magnetized along the directionof film normal, and are of great interest in postponing the onset of superparamagnetic limitationand ach
7、ieving ultra-high areal density in hard disc drives (HDDs) 125 granular film that have already been used in the commercial perpendicular HDDs 2perpendicular recording media, such as metallic multilayers 3,45,6 7,8 9,10 , have beenintensively studied as promising candidates for the future perpendicul
8、ar recording media. Amongthese materials, metal/ceramics multilayer is seldom studied to introduce strong perpendicular30 magnetic anisotropy for applications in the ultra-high density recording media. In our previouswork, we found perpendicular anisotropy was induced in the annealed CoPt/AlN multil
9、ayer 11As we increased the annealing temperature, the internal stress changed from compressive totensile, giving a positive contribution to the perpendicular anisotropy in terms of magneto-elasticanisotropy 12,133540annealing temperature, favoring the perpendicular magnetic interface anisotropy 13.A
10、lthough the origin of perpendicular anisotropy in the CoPt/AlN multilayer films was wellstudied in our previous work, the magnetic reversal mechanism is still unknown, which issignificant for the performance evaluations of the information writing process. In the present work,magnetic reversal mechan
11、ism in such highly perpendicular anisotropic CoPt/AlN multilayer hasbeen investigated by obtaining a set of magnetic hysteresis loops through systematically varyingFoundations: National Natural Science Fundation of China (No. 51201004), Research Fund for the DocoralProgram of Higher Education of Chi
12、na (No. 20121102120002), Fundamental Research Funds for the CentralUniversities (No. YWF-13-ZY-045).Brief author introduction:Yu Youxing (1982-), Male, Assistant Professor, Main research: magnetic thin films,evolutions of functional materials by using in-situ TEM, and spintroincs. -1-. The mechanism
13、 of the, which revealed that the magnetic interface anisotropy and the interfacethe angle between the applied field and the film normal. The stress-related coercive field is alsodiscussed.1 ExperimentalCoPt/AlN multilayer films were deposited on fused quartz substrates by dc magnetron4550556065sputt
14、ering at room temperature. The configuration of CoPt/AlN multilayered films is Sub/AlN5nm/CoPt2 nm/AlN5 nm5. The base pressure prior to deposition was 510-5 Pa. The sputteringwas conducted in a 0.2 Pa gas mixture of Ar and N2 with flow rates of 3.5 and 1.5 sccm,respectively. Two pairs of facing targ
15、ets were mounted into the sputtering apparatus: a pair of Cotargets partially embedded with Pt plates and a pair of Al targets. Co41Pt59 layers of solid solutionwith fcc structure were deposited at the Co-Pt targets side. AlN layers of wurtzite structure weredeposited by reactive sputtering at the A
16、l targets side. The deposited multilayers weresubsequently annealed at 500 oC for 3 h in a vacuum.The microstructure was investigated by x-ray diffraction (XRD) and transmission electronmicroscopy (TEM). The conventional Bragg-Brentano XRD profiles were measured byJDOX-3500 with Cu K irradiation operating at 40 kV and 300 mA. The cross-sectional TEMobservations were performed by a JEM-2100 transmission electron microscope operating at avolta
