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| Home > Publications database > Magnetic structure in epitaxial Fe/Cu and Fe/FePt multilayers Probed by Polarised Neutron Reflectivity |
| Home > Publications database > Magnetic structure in epitaxial Fe/Cu and Fe/FePt multilayers Probed by Polarised Neutron Reflectivity |
| Poster (After Call) | FZJ-2019-00404 |
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2015
Abstract: The study of exchange coupling effect between magnetic thin films is important due to the underlying fundamental Physics and possibility to develop functional nanostructures for their potential use in memory devices and sensors. This effect results in interlayer coupling (e.g. antiferromagnetic or biquadratic) between ferromagnetic film separated by a non- magnetic metal or semiconductor film [1-3]. The exchange coupling also emerges as exchange spring effect when soft ferromagnetic film (e.g. Fe or Permalloy) is coupled with hard ferromagnetic film (e.g. L10-FePt) [4]. It has been demonstrated theoretically that in case of exchange spring effect, magnetization of soft ferromagnet is pinned at the interface and form a spiral structure under external magnetic field [5]. It is in fact difficult to obtain the magnetic profile in exchange coupled multilayers using conventional magnetometric technique such as SQUID or MOKE. However, polarised neutron reflectivity (PNR) technique is unique to obtain depth dependent magnetization structure in magnetic thin films and multilayers. In this work we intend to use PNR technique to probe the magnetization structure in Fe layers in epitaxial Fe/Cu and Fe/FePt multilayers prepared using molecular beam epitaxy (MBE).We have deposited [Fe(1.5 nm)/Cu(2.5 nm)]10 multilayer on Cu (100) buffer layer epitaxially grown on Si (100) substrate at ~280 K. In-situ reflection high energy electron diffraction (RHEED) measurements were performed during deposition to monitor the epitaxial growth. SQUID together with PNR measurements were done to probe the interlayer coupling and magnetization structure. The temperature dependent SQUID measurement rules out the antiferromagnetic coupling between Fe layers. PNR measurements were performed at saturation, and after decreasing the field close to remanence. The spin flip PNR measurement around remnant reveals that magnetization in Fe layer is non-collinear.In order to study the exchange spring behaviour in Fe/FePt multilayers, first we deposited epitaxial FePt thin films on MgO(100) substrate at ~500 K. Ex-situ x-ray diffraction measurement confirms the L10 structure of the FePt film which has hard magnetic behaviour [6]. PNR measurements on Fe/FePt multilayers are underway, and the results of Fe/Cu and Fe/FePt multilayers will be discussed in the presentation.AcknowledgmentsI, SYED MOHD A., acknowledge the help received from Harald Schneider and Alexandra Steffen. References1. Grünberg P., Schreiber R., Pang Y., Brodsky M. B., and Sowers H., Phys. Rev. Lett. 57, 2442, (1986).2. Vaz C. A. F., Bland J. A. C., Lauhoff G., Rep. Prog. Phys. 71, 056501, (2008).3. Strijkers G. J., Kohlhepp J. T., Swagten H. J. M., and de Jonge W. J. M., Phys. Rev. Lett. 84, 1812,(2000).4. Fullerton E. E., Jiang J. S., Grimsditch M., Sowers C. H., and Bader S. D., Phys. Rev. B 58, 12193,(1998).5. Asti G., Ghidini M., Pellicelli R., Pernechele C., Solzi M., Albertini F., Casoli F., Fabbrici S., ParetiL., Phys. Rev. B 73, 094406, (2008).6. Skomski R., Manchanda P., Kumar P., Balamurugan B., Kashyap A., and Sellmyer D. J., IEEE 49,3215, (2013).
Keyword(s): Magnetic Materials (1st) ; Magnetism (2nd)
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