Edge-modulated perpendicular magnetic anisotropy in [Co/Pd]n and L10FePt thin film wires
Jinshuo Zhang1, Pin Ho1, Jean Anne Currivan-Incorvia2,3, Saima A. Afroz3, M. Baldo3,
Caroline A. Ross1
1Department
of Materials Science and Engineering, Massachusetts Institute of
Technology, Cambridge, MA 02139
2Department of Physics, Harvard University, Cambridge, MA 02138
3Department of Electrical Engineering and Computer Science, Massachusetts Institute of
Technology, Cambridge, MA 02139
Figure S1: Magnetic Force Microscopy images of [Co/Pd]20 curved nanowires prepared
with single layer resist and no edge taper. Samples were first saturated with an out-ofplane field of HSAT = +10 kOe then a reverse field of HREV was applied and samples
imaged at remanence. Bright contrast at the edges at HREV= -2000 Oe originates from
the stray field. (a) HREV = -2000 Oe; (b) HREV = -3000 Oe.
It is worth noting that although we expect reversal at the tapered edge to occur at a
lower field, the center of the tapered wire and the center of the non-tapered wire are
expected to reverse at the same field. However, the non-tapered wires and tapered
wires were grown on different substrates and there may be slight differences arising
from sample variability. For the non-tapered wires, due to side-wall deposition we need
a short sonication to complete the lift-off which may also have affected the wires and
the reversal field. This could account for differences in the domain structure at the
center of tapered and non-tapered wires (compare widest lines in Figs. 3b and S1a).
Nonetheless, it is clear that in tapered samples reversal started first at the edge
confirming the reduction of anisotropy at the edge.