Berlin 2015 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 40: Nanomaterials II: Mechanical Properties
MM 40.6: Vortrag
Mittwoch, 18. März 2015, 17:15–17:30, H 0107
Tunable magnetic anisotropy in elongated Ni nanoparticles embedded in SiO2 matrix by swift heavy ions irradiation — •Debalaya Sarker1,2, Santanu Ghosh1, Pankaj Srivastava1, and Heidemarie Schmidt2 — 1Department of Physics, Indian Institute of Technology Delhi — 2Department of Electrical Engineering and Information Technology, Technical University of Chemnitz, Chemnitz, Germany
The discovery of nanoparticle elongation inside insulator matrix by swift heavy ion (SHI) irradiation and its association to thermal spike model has led to interest in different physical properties of such systems. The ease of switching the easy axis of magnetization by elongating embedded ferromagnetic Ni nanoparticles in insulator matrix by SHI bombardment in the direction of incident beam, has motivated the present study. Ni foils glued on SiO2 target were co-sputtered. Irradiation with 100 MeV Au+7 SHI was carried out at different fluences. GISAXS analysis confirms elongation of NPs along beam direction but along with an overall volume reduction. In-plane and out-plane M-H measurements at 5 K show that gradual increase in saturation magnetization and coercivity till 5.0*1013 ions/cm2 fluence. XANES and valence band XPS show narrowest 3d electron-band for the same, resulting in maximum spin polarization. We conclude that at further higher fluences dissolution of NPs have caused overall volume reduction and hence results in reduction of shape anisotropy originated perpendicular magnetization. Thus the intermediated fluence irradiated film, having the maximum out of plane magnetization, can find its promising applications in future perpendicular magnetic storage devices capable of thrice storage capacity in comparison to normal linear storage media.