Magnetic Yoking and Tunable Interactions in FePt-Based Hard/Soft Bilayers.
Magnetic interactions in magnetic nanostructures are critical to nanomagnetic and spintronic explorations. Here we demonstrate an extremely sensitive magnetic yoking effect and tunable interactions in FePt based hard/soft bilayers mediated by the soft layer. Below the exchange length, a thin soft layer strongly exchange couples to the perpendicular moments of the hard layer; above the exchange length, just a few nanometers thicker, the soft layer moments turn in-plane and act to yoke the dipolar fields from the adjacent hard layer perpendicular domains. The evolution from exchange to dipolar-dominated interactions is experimentally captured by first-order reversal curves, the ΔM method, and polarized neutron reflectometry, and confirmed by micromagnetic simulations. These findings demonstrate an effective yoking approach to design and control magnetic interactions in wide varieties of magnetic nanostructures and devices.
Dept. of Physics, University of California, Davis, California 95616, USA.|NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA.
Dustin A
DA
Gilbert
Dept. of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
Jung-Wei
JW
Liao
NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA.
Brian J
BJ
Kirby
Dept. of Earth and Environmental Sciences, Geophysics, Munich University, 80333 Germany.|Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany.|IBU, School of Mathematics and Science, Carl von Ossietzky University, 26129, Oldenburg, Germany.
Michael
M
Winklhofer
Dept. of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
Chih-Huang
CH
Lai
Dept. of Physics, University of California, Davis, California 95616, USA.
Kai
K
Liu