Magnetic domain wall pinning and coercivity in FePt/MgO and FePt/Pt thin films

Jourdan, Thomas; Attané, J. P.; Lançon, Frédéric; Beigné, C.; Vila, Laurent; Marty, A.

doi:10.1016/j.jmmm.2009.01.030

Cited by 11 publications

(4 citation statements)

References 20 publications

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“…For this purpose, we simulated wires tailored in FePt/MgO thin films, with very large crystal anisotropy. 24 The simulated sample has a size of 80ϫ 50ϫ 5 nm 3 and includes a defect in the center with a size of 5 ϫ 10ϫ 5 nm 3 ͓Fig. 4͑a͔͒.…”

Section: Thermal Depinning From Single Defectmentioning

confidence: 99%

Effect of crystalline defects on domain wall motion under field and current in nanowires with perpendicular magnetization

et al. 2010

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In this work, we present a micromagnetic study of a magnetic domain wall dynamics influenced by magnetic fields and/or spin-polarized currents in systems characterized by perpendicular magnetization including crystalline defects. The dynamics in two different systems is studied: one showing the effect of defects in the flow regime, and the second one presenting the thermally activated depinning from a single defect. In the latter case, the thermal depinning can be analyzed within the framework of a single energy barrier process. In such situation, the current density can be assimilated to an applied field. We found that the energy barrier depends linearly on the applied field and on the injected current.

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Section: Thermal Depinning From Single Defectmentioning

confidence: 99%

Effect of crystalline defects on domain wall motion under field and current in nanowires with perpendicular magnetization

et al. 2010

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“…The H c,⊥ and ρ dis of FePt films are increased with increasing heating rate of RTA, but ρ SF is almost independent of heating rate, demonstrating that the ρ dis shows a close relation to H c,⊥ in FePt films. Therefore, dislocations in FePt films act as dominant domain-wall pinning sites to restrict domain-wall motion, , and the domain-wall motion will be harder with higher dislocation density, indicating that the H c,⊥ of FePt films is improved by the increase of dislocation density.…”

Section: Resultsmentioning

confidence: 99%

“…Several factors that can affect the H c of the L1 0 FePt films have been reported, including changes in the magnetic anisotropy ( K u ), L1 0 ordering parameter, , grain sizes, grain boundaries, dislocation, − stacking fault, , twinning densities, and doping . However, the overall magnetic properties are most affected by the RTA treatment process, which we focus on here.…”

Section: Introductionmentioning

confidence: 99%

L1₀ FePt Films with Optimal (001) Texture on Amorphous SiO₂/Si Substrates for High-Density Perpendicular Magnetic Recording Media

Chiou

Chang

Chi

et al. 2019

ACS Appl. Nano Mater.

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Highly ordered L10 FePt films with the highest degree of [001] preferred orientation were prepared by multilayer deposition on amorphous oxidized Si substrates and subsequent rapid thermal annealing (RTA). We identify how to synthesize the preferred orientation structure on the amorphous substrate, which we find to be critical to the optimal formation of the [001] preferred orientation. This was achieved by controlling the heating rate of the RTA process. We also identify how the influence of the beam power, sputtering working pressure, and annealing time affect the structural and magnetic properties of FePt films. For example, a L10 preferred orientation and increased magnetic anisotropy of the FePt films have been attained by composition and in-plane tensile stress adjustments. The perpendicular field coercivity was enhanced by increasing the RTA heating rate, which increased the dislocation densities induced by strain. We also found that the strain fields of dislocations in FePt L10 films can act as the dominant pinning sites that restrict domain wall motion, increasing the coercivity. We find that this is due to the spatial range of the strain fields associated with dislocations being similar to the domain wall width in the films.

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“…Here α is the Gilbert damping constant, and H eff is the effective magnetic field including the external, exchange, demagnetizing, and crystalline anisotropic fields. Material parameters are as follows [34][35][36] [37] in each wire as a function of the magnetic field applied along the out-of-plane direction. A high-field regime for FePt is shown in the bottom-right inset.…”

mentioning

confidence: 99%

Stability of spinmotive force in perpendicularly magnetized nanowires under high magnetic fields

Yamane

Ieda

Maekawa

2012

Applied Physics Letters

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Spinmotive force induced by domain wall motion in perpendicularly magnetized nanowires is numerically demonstrated. We show that using nanowires with large magnetic anisotropy can lead to a high stability of spinmotive force under strong magnetic fields. We observe spinmotive force in the order of tens of µV in a multilayered Co/Ni nanowire and in the order of several hundred µV in a L10-ordered FePt nanowire; the latter is two orders of magnitude greater than that in permalloy nanowires reported previously. The narrow structure and low mobility of a domain wall under magnetic fields in perpendicularly magnetized nanowires permits downsizing of spinmotive force devices.The mutual interaction between spin current and magnetization is a key phenomenon in the field of spintronics [1]. Spin current induces magnetization dynamics, i.e., spin-transfer-torque [2][3][4][5], which has been extensively studied through current-induced domain wall (DW) motion, primarily in permalloy (NiFe) nanowires with in-plane magnetization [6][7][8][9][10]. Recently, it has been reported experimentally [11,12] and theoretically [13,14] that nanowires with perpendicular magnetic anisotropy (PMA) are more favorable for spin-transfer-torque devices because they exhibit DW motion at a lower threshold current. On the other hand, the same interaction mediates energy-transfer from magnetization into conduction electrons, i.e., spinmotive force (SMF) [15]. Like the spin-transfer-torque [16] and other spin-related electromotive forces [17,18], SMF offers a promising functionality for future spintronic devices; e.g., it can be used to read out magnetic information [19]. SMF has been primarily demonstrated in NiFe [20][21][22][23][24][25], and only few reports have demonstrated SMF in PMA materials [26]. However, the soft magnetic properties of NiFe could occasionally be a major disadvantage for an SMF demonstration; certain magnetization structures are easily disturbed by a strong magnetic field, leading to an increased instability in SMF signals. Therefore, SMF induced by DW motion in NiFe nanowires is limited to a few µV [20,25].In this paper, the SMF induced by DW motion in PMA nanowires is numerically investigated. The abovementioned problem in the NiFe nanowires is resolved by using PMA nanowires, which show rigid DW motion because of their high magnetic anisotropy. It has been shown that materials with the high PMA are effective in achieving a large SMF. We numerically observe SMF in the order of tens of µV in a multilayered Co/Ni nanowire and in the order of several hundred µV in a L1 0 -ordered FePt nanowire with the very large PMA. In addition, the narrow structure and low mobility of a DW in PMA nanowires are effective in downsizing of devices using SMF.Let us begin by assessing SMF induced by DW motion in NiFe nanowires. It has been pointed out that SMF is generally produced by the spin electric field[27-31];where m is the unit vector parallel to the direction of local magnetization of the ferromagnet, P is the average spin polarizatio...

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Magnetic domain wall pinning and coercivity in FePt/MgO and FePt/Pt thin films

Cited by 11 publications

References 20 publications

Effect of crystalline defects on domain wall motion under field and current in nanowires with perpendicular magnetization

Effect of crystalline defects on domain wall motion under field and current in nanowires with perpendicular magnetization

L1₀ FePt Films with Optimal (001) Texture on Amorphous SiO₂/Si Substrates for High-Density Perpendicular Magnetic Recording Media

Stability of spinmotive force in perpendicularly magnetized nanowires under high magnetic fields

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Magnetic domain wall pinning and coercivity in FePt/MgO and FePt/Pt thin films

Cited by 11 publications

References 20 publications

Effect of crystalline defects on domain wall motion under field and current in nanowires with perpendicular magnetization

Effect of crystalline defects on domain wall motion under field and current in nanowires with perpendicular magnetization

L10 FePt Films with Optimal (001) Texture on Amorphous SiO2/Si Substrates for High-Density Perpendicular Magnetic Recording Media

Stability of spinmotive force in perpendicularly magnetized nanowires under high magnetic fields

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L1₀ FePt Films with Optimal (001) Texture on Amorphous SiO₂/Si Substrates for High-Density Perpendicular Magnetic Recording Media