Stripe Domain Width Research Articles

Scratching-induced large-area and tunable perpendicular anisotropy in flexible metallic glass under ambient conditions

The scratching-induced tunable perpendicular anisotropy in amorphous FeSiB ribbon surface has been directly observed in room temperature and air atmosphere. The magnetic stripe domain width and contrast strength can be easily tuned according to the scratch size, and the magnetic signature is erasable in nano-scale by indentation, which greatly facilitates the direct magnetic patterning. The result presents a simple way of fabricating the large-area magnetic film with controllable perpendicular anisotropy, remarkable intrinsic flexibility and high strength directly from amorphous FeSiB ribbon under ambient conditions, which may simulate much scientific and engineering interest, leading to the novel applications of metallic glasses.

Magnetic stripe melting at the spin reorientation transition inFe∕Ni∕Cu(001)

Magnetic stripe domains in $\mathrm{Fe}∕\mathrm{Ni}∕\mathrm{Cu}(001)$ were imaged and studied using photoemission electron microscopy. The stripe domain width decreases exponentially as the system approaches the spin reorientation transition (SRT) point. A reduction of the Curie temperature $({T}_{C})$ is observed within a narrow gap of the SRT region. For film with fixed thickness, the stripe domains below ${T}_{C}$ represent only part of the stripe phase due to a higher SRT temperature than ${T}_{C}$.

Magnetic stripe domains in coupled magnetic sandwiches.

Magnetic stripe domains in the spin reorientation transition region are investigated in (Fe/Ni)/Cu(001) and Co/Cu/(Fe/Ni)/Cu(001) using photoemission electron microscopy. For (Fe/Ni)/Cu(001), the stripe domain width decreases exponentially as the Fe/Ni film approaches the spin reorientation transition point. For Co/Cu/(Fe/Ni)/Cu(001), the Fe/Ni stripe orientation is aligned with the Co in-plane magnetization, and the stripe domain width decreases exponentially with increasing the interlayer coupling between the Fe/Ni and Co films. By considering magnetic stripes within an in-plane magnetic field, we reveal a universal dependence of the stripe domain width on the magnetic anisotropy and on the interlayer coupling.

MFM imaging of FePd stripe domains. Evolution with Pt buffer layer thickness

Epitaxial FePd (0 0 1) thin films grown by UHV sputtering onto different Pt buffer layers have been studied by magnetic force microscopy. Samples with buffer thickness down to 150 Å present high perpendicular magnetic anisotropy. Both the stripe domain width and the magnetic contrast increase with the buffer thickness, in agreement with the anisotropy deduced from the hysteresis loops.

Magnetoresistance due to domain walls in an epitaxial microfabricated Fe wire

The domain wall (DW) contribution to magnetoresistance has been investigated using an epitaxial microfabricated bcc (110) Fe wires of 2 μm linewidth. A strong in-plane uniaxial component to the magnetic anisotropy perpendicular to the wire axis causes a regular stripe domain pattern with closure domains. The stripe domain width in zero-applied magnetic field is strongly affected by the magnetic history and can be continuously varied from 0.45 to 1.8 μm. This enables a measurement of the resistivity as a function of DW density in a single wire. Clear evidence is presented that the resistivity is reduced in the presence of DWs at low temperatures.

Domain formation in thin ferroelectric films: The role of depolarization energy

Formulae for equlibrium stripe domain width Weq in a nonductive ferroelectric plate of thickness d are deduced, taking into account electrostatic interaction of surfaces. It is shown that the classical formula giving W eq ∞ d 1/2 is not applicable when the sample thickness decreases below the value dcrit which is a function of dielectric properties and domain wall energy density. For many ferroelectrics the value of dcrit lies in a range which can be easily reached far below the transition point by contemporary thin film techniques; it further increases as the transition point is approached. In the region d < dcrit the width Weq increases with decreasing d. For samples with thickness d << dcrit the domain structure becomes insensitive to electrical boundary conditions and will be primarily determined by other factors.

Domain structures and magnetic properties of FeN films sputter-deposited on sloping surfaces

We obtained soft magnetic properties of FeN on sloping substrates by lamination with thin AlN interlayers. Single layer FeN films on sloping substrate have large saturation field and small squareness. The cause of the degradation of soft magnetic properties in single layer films is ascribed to the perpendicular anisotropy. The existence of the perpendicular anisotropy of FeN sputter-deposited on sloping surfaces is confirmed by the observation of stripe domains with magnetic force microscopy. The observed values of the stripe domain width and the critical film thickness are compared with the calculated values. The stripe domains are parallel to the applied field direction when a saturation field is applied prior to the observation. The stripe domains rotate with the applied field direction.

Incoherent rotations in thin films with in-plane anisotropy

The hard axis magnetization process in thin ferromagnetic films has been investigated by Lorentz electron microscopy. At the onset of an external magnetic field the local magnetization vectors of the individual domains rotate incoherently. To describe these rotations an internal field is introduced. The magnitude of this field and its evolution during the magnetization process are calculated in terms of experimentally measured directions of local magnetization. The internal field increases as the domains appear, attaining two extreme values and then gradually vanishes close to saturation. Its maximum value depends on the width of stripe domains arising when the film is magnetized along the hard axis. The internal field is the main factor determining the shape of the hysteresis loop.

The temperature dependence of domain wall energy in TmFeO 3

The domain structure of single-crystal thulium orthoferrite (in a plane perpendicular to the a-axis) was studied in the temperature range 4.2–94 K. The temperature dependence of the stripe domain width as well as of the domain wall energy density was determined. Obtained results, together with results of other authors for the range 80–300 K, were analysed in the molecular field approximation.

Submicron magnetic bubble material of (YSmLu)3(FeGaSc)5O12

A new submicron magnetic bubble garnet of (YSmLu)3 (FeGaSc)5O12 with low saturation induction 4πMs if found. By suitable combination of amounts of Ga and Sc, 4πMs can be kept to a practical minimum. The usefulness of substitution for ferric ions in both tetrahedral and octahedral sites by nonmagnetic ions for the reduction of 4πMs in submicron bubble garnets is shown. For example, films with the following properties are grown: stripe domain width w=0.9 μm; characteristic length l=0.10 μm quality factor q=2.6; and 4πMs=600 G.

Amorphous Gd-Fe alloy films prepared by RF cosputtering technique

Amorphous Gd <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> Fe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf> (0 < x < 0.35) thin films were prepared by RF cosputtering using an iron target covered partially with small gadolinium pieces. The composition dependences of saturation magnetization, hysteresis curves, and domain structures were studied. Spark-like domains were observed when the magnetization was reversed from saturation. The uniaxial anisotropy was induced perpendicular to the film plane. The average value of the perpendicular uniaxial anisotropy constant Ku was about 2 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> erg/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Ku, however, decreases as the saturation moment decreases in the vicinity of room temperature compensation. The stripe domain width was varied from 0.3 to 4 microns as the saturation moment decreased from 300 to 20 gauss. These magnetic properties of amorphous Gd-Fe sputtered films are similar to those of amorphous Gd-Co films.

Stripe domains in arbitrarily oriented fields

We have calculated the width of stripe domains in uniaxial magnetic films in a static uniform applied field of arbitrary magnitude and orientation. The results are in good agreement with reported experimental results.

Domain growth in thin MnBi films

The influence of the coercive force, H c , on domain growth in MnBi films is investigated on a local scale. It is found that for domain tip movement to occur, a critical domain width has to be exceeded. When H c is in the same order of magnitude of the magnetostatic pressures, this critical width is restored in the final stripe domain width, which is considerably greater than the equilibrium domain width in the absence of H c .