| AVS 57th International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures | Thursday Sessions |
| Session MI+TF-ThM |
| Session: | Magnetic Nanostructures, Thin Films and Heterostructures |
| Presenter: | Z. Gai, Oak Ridge National Laboratory |
| Authors: | X.G. Zhang, Oak Ridge National Laboratory I.I. Kravchenko, Oak Ridge National Laboratory S.T. Retterer, Oak Ridge National Laboratory J.F. Wendelken, Oak Ridge National Laboratory Z. Gai, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
For thin films, the generalized Curie-Weiss law extends the power law scaling well above Tc by replacing the linear reduced temperature tL by a nonlinear reduced temperature tNL=1-Tc/T. The film thickness d and temperature T are usually not independent variables in the scaling. Using the nonlinear reduced temperature, the power law scaling was shown to be accurate over the entire paramagnetic regime [1-3]. However, at low temperature, thermally activated domain wall motion is expected to contribute significantly to the temperature dependence of magnetic properties, therefore the scaling law is generally believed not to extend far below Tc. Such belief was contradicted by a very recent experiment [4] that showed a surprising power law scaling for the in-plane susceptibility of sputtered Ni films deposited on silicon for the entire temperature range between zero and Tc. In addition, thickness and temperature dependence are completely decoupled. This scaling result implies that even in the ferromagnetic regime, there is no domain wall motion contribution to the low field susceptibility [4]. To clarify the role of domain wall motion, arrays of single domain Ni microstructures are studied experimentally and theoretically. We will show the results of the AC susceptibility measurements of Ni microstructures with magnetic single domain, in which the contributions of domain wall motion and spin fluctuation to the susceptibility are separated.
This research at Oak Ridge National Laboratory's Center for Nanophase Materials Sciences was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.
[1] H. Lutz, P. Scobsria, J. E. Crow, and T. Mihalism, Phys.Rev. B 18, 3600 (1978).
[2] M. Fahnle and J. Souletie, J. Phys.c 17, L469 (1984).
[3] A. S. Arrott, Phys. Rev. B 31, 2851 (1985).
[4] X. H. Song, X.-G. Zhang, J. Fan, Y. R. Jin, S. K. Su, and D. L. Zhang, Phys. Rev. B 77, 092408 (2008).