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MA: Fachverband Magnetismus
MA 11: Magnetic Thin Films I
MA 11.4: Talk
Tuesday, March 27, 2007, 11:00–11:15, H10
Magnetocrystalline Anisotropy in Permalloy Revisited — Lifeng Yin1, Dahai Wei1, Na Lei1, •Lihui Zhou1, Chuanshan Tian1, Guosheng Dong1, Xiaofeng Jin1, Liping Guo2, Quanjie Jia2, and Ruqian Wu3 — 1Surface Physics Laboratory, Fudan University, Shanghai 200433, China — 2Beijing Synchrotron Radiation Facility, Beijing 100049, China — 3Department of Physics and Astronomy, University of California at Irvine, Irvine, California 92697, USA
We present our observation on the magnetic properties of Permalloy (Py) with a bcc structure1 to address the long-standing issue that why Py is a soft magnet.
bcc Py, which does not exist in nature, has been achieved on GaAs(001) by molecular beam epitaxy at 200K. It is ferromagnetic with the Tc lower than that of the conventional Py - its fcc counterpart, and with the magnetic moment almost equal to that of fcc Py. Most strikingly, depending not on the atomic structure but only on the stoichiometry of Fe and Ni of the alloy, the cubic magnetocrystalline anisotropy of bcc Py is also vanishing, which directly challenges the standard cancellation model2. The experimental result is further confirmed by first-principles electronic-structure calculations, and attributed to the charge redistribution after alloying.
1.L. F. Yin et al., Phys. Rev. Lett. 97, 067203 (2006). 2.Derek Craik, Magnetism: Principles and Applications (John Wiley and Sons, Chichester, 1995), p. 392.