(a) The composition and structure of the Co/Pd multilayer system. (b) Hysteresis loops measured for the easy axis (solid/green; perpendicular to the sample plane) and for the hard axis (dotted/red; parallel to the sample plane) by SQUID magnetometry. In the inset a magnified view of the central part of the loops is shown to facilitate the estimation and comparison of the coercivities.
(a) The topography and domain structure of the as-grown sample imaged by AFM and MFM, respectively; the scale bar on the right of the AFM and MFM image represents the height contrast scale for AFM and magnetic contrast scale (phase shift) for MFM; the rms-roughness measured by AFM was approximately 1 nm. (b) The growth of a domain by domain wall propagation recorded in three consecutive Kerr microscopy images at an external reversal field of −66.8 mT.
[(a) and (c)] Simulated two-beam and three-beam laser interference pattern, respectively. [(b) and (d)] Topography images (AFM) of the Co/Pd multilayer system structured with two-beam laser interference and with three-beam laser interference, respectively.
(a) Focused polar MOKE hysteresis loop and (b) MFM micrographs recorded at different remanent magnetizations . The measurements were carried out in a region irradiated at high laser intensity (region I).
Kerr microscopy images of magnetization reversal in region I. [(a)–(c)] Sample patterned with two-beam interference. [(d)–(f)] Sample patterned with three-beam interference.
(a) Focused polar MOKE hysteresis loop and (b) MFM micrographs recorded at different remanent magnetizations. The measurements were carried out in a region irradiated at medium laser intensity (region II). The dotted red circles mark the field threshold above which the hillocks start to switch.
Kerr microscopy images of magnetization reversal in region II. [(a)–(c)] Sample prepared with two-beam interference. [(d)–(f)] Sample patterned with three-beam interference. The thin horizontal line in (a)–(c) is a scratch on the surface, which acts as a nucleation site.
(a) AFM and (b) MFM micrographs of region III (region irradiated at very low intensity) on a sample patterned with three-beam interference. The flattened area in (b) was scanned twice and shows the magnetic contrast recorded at the second run. The first scan started from the middle line and ended approximately above.
Schematic plots. (a) Coercivity of laser irradiated Co/Pd multilayer vs laser intensity and (b) intensities of interference maxima and minima, and , respectively vs distance from the center of the laser spot. The inset on the right shows an MFM micrograph of a transition region between regions I and II. is the coercivity of the as-grown sample. The yellow and blue shaded areas represent the range of intensity with which a certain location within regions I and II, respectively, has been irradiated. and denote the smallest nucleation field at a certain location in regions I and II, respectively. and are the threshold intensities above which the laser irradiation starts to change and domain wall motion along the valleys is entirely inhibited, respectively.
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