Magnetic domains in epitaxial nanomagnets with uniaxial or fourfold crystal anisotropy

Abstract

In order to prepare submicron sized particles with strong magnetocrystalline anisotropies high quality epitaxial bcc-Fe films were grown on GaAs(110) and GaAs(001) by molecular beam epitaxy. Whereas Fe(110) on GaAs(110) is a model system with uniaxial in-plane anisotropy, Fe(001) on GaAs(001) has a strong fourfold anisotropy for films thicker than ∼5 nm. Various shapes like circular, square, or rectangular elements with sizes from 200 nm up to 6 μm were fabricated by electron beam lithography and ion beam etching. The remanent states after saturation along different directions or ac demagnetization along the easy axis were examined by using magnetic force microscopy. The experimental results clearly reflect the interplay of the different magnetocrystalline and shape anisotropies depending on the different magnetic histories.

Micromagnetic studies of cobalt microbars fabricated by nanoimprint lithography and electrodeposition

“…2c and d was observed in long permalloy bars magnetized along the short axis ( [32] Fig. 4b, middle image), but the reference [32] does not provide the explanation on the magnetization configuration of the elements.…”

Size and orientation effect on micromagnetic states in rectangular epitaxial Fe (011) microstructures

“…Epitaxial Fe films were grown on the A-plane of sapphire Al 2 O 3 (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) with a Mo seed layer 10 nm thick by pulsed laser deposition in ultrahigh vacuum. The thickness of Fe (011) films was 60 nm and was controlled with a profilometer.…”

“…Therefore, microstructures fabricated on the basis of iron exhibit another sequence of magnetic states at the size decrease. Microstructures in the form of strips, rectangles and rectangles with sharpened ends fabricated on the basis of epitaxial Fe (001) and Fe (011) films were studied in [10][11][12][13][14][15][16]. It was found that micromagnetic states and mechanisms of magnetization reversal in microstructures with a lateral size smaller than 50 mm differ from those in film structures [10].…”

Observation of a geometrically constrained domain wall in epitaxial FCC Co small disks

“…Whereas the effect of the physical shape of the element has been well studied [1-3] the role of the magnetic anisotropy has not been so extensively investigated [3][4][5]. In general, the effect of the magnetic anisotropy is to restrict the states with flux closure to those compatible with local domains pointing along the easy direction axis.…”