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Magnetic skyrmions are promising building blocks for developing information storage and computing devices. It can be stabilized in a ferromagnetic thin film with the Dzyaloshinskii-Moriya interaction (DMI). The moving ferromagnetic skyrmion may show the skyrmion Hall effect, that is, the skyrmion shows a transverse shift when it is driven by a spin current. Here, we numerically and theoretically study the current-driven dynamics of a ferromagnetic nanoscale skyrmion in the presence of the anisotropic DMI, where the skyrmion has an elliptical shape. The skyrmion Hall effect of the elliptical skyrmion is investigated. It is found that the skyrmion Hall angle can be controlled by tuning the profile of the elliptical skyrmion. Our results reveal the relation between the skyrmion shape and the skyrmion Hall effect, which could be useful for building skyrmion-based spintronic devices with a preferred skyrmion Hall angle. Also, our results provide a method for the minimization of the skyrmion Hall angle for applications based on in-line motion of skyrmions. [ABSTRACT FROM AUTHOR]

The longitudinal CoCrPt thin films have been prepared on CrW underlayer at room temperature. The dependence of CoCrPt’s structure and magnetic properties on the Pt content was investigated. The addition of platinum element in the CoCrPt magnetic layer increases the lattice constant and longitudinal coercivity of the CoCrPt thin films. The coercivity mechanism of the CoCrPt thin film is analyzed by using the micromagnetic models, with careful discussions of the uniaxial crystalline anisotropy and the magnetostriction. It is found that the magnetostriction effects play an important role on the coercivity mechanisms when the Pt content is more than 15 at. % Pt concentrate. [ABSTRACT FROM AUTHOR]

Co-ferrite thin film with spinel structure is attractive for spintronics and multifunctional devices. So far, single-crystal substrates are necessary to introduce perpendicular magnetic anisotropy in co-ferrite films. In this paper, a unique process has been developed to deposit co-ferrite thin films onto thermally oxidized silicon wafer with perpendicular magnetic anisotropy. We have successfully prepared co-ferrite films with (00l) orientation. Those films show perpendicular coercivities as large as 12.8 kOe. X-ray diffractometry results revealed that compressive strain, which is introduced by the postannealing process rather than deposition process, is as large as 1.3% in films with (00l) orientation. The large coercivity and perpendicular magnetic anisotropy can be quantitatively explained by the magnetoelastic effect. This silicon-compatible fabrication process is useful to further extending the applications of co-ferrite films. [ABSTRACT FROM AUTHOR]

Magnetic force microscope (MFM) probes are fabricated by coating magnetically soft FeCo films in a facing targets sputtering (FTS) system. Compared with DC magnetron sputtering, probes coated by FTS show smaller tip radius. Lateral resolution about 12 nm has been achieved by the probes. Simulation results show that a magnetic vortex is formed at the probe apex. The resulting effective magnetic moment of the probes will be minimized by the formation of vortex. We show that these probes have higher lateral resolution than the standard, commercially available MFM probes. [ABSTRACT FROM PUBLISHER]

A method of introducing pinning sites in TbFeCo film by the using of focused ion beam was presented. The formed bulges in the film surface by discontinuous scan of light-dose focused ion beam have been proved to enhance the film's coercivity effectively. Coercivity increases almost linearly with the bulge density, giving the evidence of pinning effect contributed from those bulges predicted by domain wall pinning mechanism. Compared with the traditional way of etching the film for adjusting the coercivity, the method presented here shows superiority on reducing magnetic damage to film caused by the focused ion beam irradiation. [ABSTRACT FROM PUBLISHER]

Substituted strontium ferrite (\SrFe12-x{(\Cr0.5\Al0.5)}_x\O19) thin films were formed along the surface of multiwalled carbon nanotubes (MWCNTs). Mössbauer spectroscopy indicates that the substituted cations preferentially occupy the 12k sites. X-ray diffraction (XRD), transmission electron microscope (TEM), field emission scanning electron microscope (FE-SEM), vibrating sample magnetometer (VSM), and vector network analyzer were used to analyze the structure, static, and high-frequency magnetic properties of the prepared samples. It was found that with an increase in substitution content, the saturation of magnetization decreases while the coercivity increases. The CNTs could enhance the real and imaginary parts of permittivity of ferrites. With an increase in volume percentage of MWCNTs, the reflection loss values were increased. [ABSTRACT FROM AUTHOR]

Abstract: Sm–Co and Nd–Fe-B thin films have been prepared by sputtering. Particular efforts are concentrated on the perpendicular texture growth of the films. The Sm–Co and Nd–Fe–B thin films with perpendicular magnetic anisotropy can be prepared on Cu and W underlayer, respectively. Those underlayers play an important role to prevent oxidation and improve crystal lattice orientation. Perpendicular coercivity and remanent squareness ratio are higher than 10kOe and almost 1.0, respectively, in both films prepared under optimum conditions. [Copyright &y& Elsevier]

High saturation magnetization FeCo(Fe65 Co35)/Co films with 4πM8 about 24 kG were prepared by facing targets sputtering (FTS). A well-defined in-plane uniaxial anisotropy and excellent soft magnetic properties were obtained with a hard axis coercivity of Hch = 3 Oe by inserting a thin Co underlayer. The X-ray diffractometry (XRD) results indicate that the Co underlayer changed the main diffraction line from (200) in the FeCo single layer to (110) in the FeCo/Co films. The Co underlayer significantly reduced the average grain size from ∼74 nm for FeCo single layer to ∼8.2 nm for FeCo/Co films. A smoother surface and a narrower grain size distribution were observed in FeCo/Co films. [ABSTRACT FROM AUTHOR]

Abstract: Pt, Pd, and Pt–Pd alloy underlayers were used to deposit c-axis oriented barium ferrite (BaM) thin films by a facing target sputtering system. All of the BaM thin films grown on these three underlayers show c-axis orientation normal to the film plane. But the grain size of BaM layer is strongly manipulated by the underlayer grain size. It is found that Pt–Pd alloy underlayer is effective to achieve c-axis oriented barium ferrite films with small grain size. [Copyright &y& Elsevier]

5 × 25 mm FeCoAlO gradient composition thin film was prepared with composite target by using RF magnetron sputtering. The Al-O composition gradient along the length direction of the film was introduced by Al2O3 chips asymmetrically arrayed on a Fe70Co30 target disk. The film was divided into five equal segments. All samples showed a low coercive force Hc of 4 - 8 Oe. The saturation magnetization 4πMs increased continuously from 17.3 kGs for sample 1 (has more Al-O content) to 19.7 kGs for sample 5 and it was consistent with the increasing of Fe-Co composition. Meanwhile, these samples showed different anisotropy behaviors relating with Al-O composition. The sample 1 exhibited the same magnetization curve along the directions of G| and G⊥ (G| and G⊥ are parallel and perpendicular to the direction of the Al-O composition gradient, respectively). In both of G| & G⊥ directions, the sample 1 showed a resonance frequency (fr) of around 2.6 - 3.0 GHz, while, in G| direction, it showed a high value of real permeability μ′. The sample 5 exhibited a distinct in-plane uniaxial anisotropy and a good high-frequency response of 3.0 GHz resonance frequency. So these films having gradient composition exhibit are suggested for the use in integrated magnetic devices working in the GHz frequency range. [ABSTRACT FROM AUTHOR]

The soft magnetic FeCoAlO thin films with different response at high frequency were prepared by using RF magnetron sputtering. Two different configurations of the sputtering targets were used: the Al2O3 chips were placed on Fe70Co30 disk either uniformly dispersed on the sputtering area (Target-A) or dispersed on the half side of the sputtering area (Target-B). It was found that, although, the films deposited from both of Target A and B possessed good soft magnetic properties and in-plane uniaxial magnetic anisotropy, they showed different behaviors at high frequency. The films deposited by using Target-A have mean permeability of 500 and a cut-off frequency (fr) of around 780 MHz, while the films deposited by using Target-B have mean permeability of 200 and a fr of 3.4 GHz. The higher fr of the later corresponds to the higher uniaxial anisotropic field in the films deposited by using the Target-B, which due to an extra anisotropy induced by the stress resulted from gradient of the Al-O composition. By adjusting the configuration of Target-B, the permeability & fr can be tuned to satisfy the different requirements for certain industrial applications. [ABSTRACT FROM AUTHOR]

Abstract: A new technique, which utilizes the interlayer diffusion, for preparation of self-assembled nanodot magnetic structures has been proposed. L10-phase Pt/FeCu and Pt/FeAg films have been successfully synthesized by this technique. Both the coercivity of Pt/FeCu and Pt/FeAg films exhibited, respectively 4.1 and 8.0kOe in perpendicular direction. Pt/Fe and Pt/FeAg films show positive values, while Pt/FeCu shows negative value in δm plot. The results indicate that the exchange coupling between the grains has been decoupled in the self-assembled nanodot structure in Pt/FeCu film. [Copyright &y& Elsevier]

Abstract: TiN thin film is prepared by DC reactive sputtering in Ar+N2 atmosphere and its suitability as underlayer and overlayer for TbFeCo perpendicular recording media as well as its effect on the magnetic properties of the latter have been studied. Only 5nm TiN overlayer and 20nm under layer can successfully protect the TbFeCo film from oxidation. Initially the coercivity is increased sharply from about 2 to 6kOe for an increase of underlayer thickness to 60nm then the increasing rate of coercivity becomes very slow. The saturation magnetization remains almost constant with the underlayer thickness. The remanent squareness ratio remains constant at 1.0 with the underlayer thickness up to 60nm then decreases. [Copyright &y& Elsevier]

Abstract: Strontium ferrite (SrM) thin films were deposited on thermally oxidized silicon wafer with Au underlayer. Gold underlayers were prepared at various substrate temperatures by using a magnetron sputtering system. C-axis oriented SrM perpendicular films and preferred (111) orientation of underlayer have confirmed by X-ray diffraction patterns. The intensity of (111) diffraction line for Au and that of (00 l) diffraction line for strontium ferrite decrease with increase in substrate temperature (T u) The maximum coercivity and remanent squareness ratio in perpendicular direction, at T u of 500°C, are 5.4kOe and 0.68, respectively. The strength of the intergranular interaction of SrM magnetic particles is described by the parameter Δm. The SrM/Au films prepared at T u above 100°C have smaller Δm peak values than that for SrM/Au films prepared at T u of room temperature. This behavior is related to low magnetostatic coupling between the magnetic particles separated by the non-magnetic amorphous phase. [Copyright &y& Elsevier]

Thin films of Ba-Me ferrites are synthesized by reactive rf diode sputtering of a BaO · nFe[sub 2]O[sub 3] ceramic target. Quartz plates subjected to preliminary annealing are used as substrates. The influence of the barium ion content on the crystalline and magnetic properties and the microstructure of the prepared films is investigated, and the interrelation between the quantity dH[sub c]/dT and the microstructure of the film is considered. The prepared films satisfy the requirements for materials used as information carriers with a superhigh recording density. [ABSTRACT FROM AUTHOR]