Plasma-induced magnetic patterning of FePd thin films without and with exchange bias

Wang, Wei Hsiang; Chang, Po Chun; Jiang, Pei-hsun; Lin, Wen Chin

doi:10.1016/j.apsusc.2020.146831

Cited by 6 publications

(6 citation statements)

References 52 publications

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“…All the hysteresis loops are measured from the area inside the single square at the top left corner and from the outside area next to it on the right, respectively (see the Supplementary Materials). Note that possible PMMA remnants would not contribute to any field-dependent MOKE signals, as already confirmed in our previous studies [12]. Oe.…”

Section: Methodssupporting

confidence: 85%

“…The remnant contrast under saturation is often detected in our studies on CoPd or FePd thin films with their magnetic domain patterns created using lithography and plasma treatments. Further investigation of these samples using zero-field polar MOKE microscopy shows clear contrasts of the squares [12], which reveal the difference in the perpendicular magnetization between and areas inside and outside the squares. This may explain the existence of the magnetic contrast between the two regions even under saturation.…”

Section: Resultsmentioning

confidence: 97%

“…Evolution of metal-oxide growth under different oxidation conditions has also become an important topic [6,7,8,9,10], including a special focus on self-assembly integrated with conventional photo or e-beam lithography that has been shown to be a powerful tool to achieve complex multiple patterning [11]. Since patterned oxidation can be utilized for sophisticated engineering of magnetic structures in thin films [12], lithography incorporated with different types of oxide formation is expected to boost the beneficial application of magnetic patterning.…”

Section: Introductionmentioning

confidence: 99%

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Dependence of magnetic domain patterns on plasma-induced differential oxidation of CoPd thin films

Wang,

Liu,

Chuang

et al. 2021

Preprint

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We demonstrate the evolution of the micro-patterned magnetic domains in CoPd thin films pretreated with e-beam lithography and O 2 plasma. During the days-long oxidation, significantly different behaviors of the patterned magnetic domains under magnetization reversal are observed via magneto-optic Kerr effect microscopy on different days. The evolution of the magnetic behaviors indicate critical changes in the local magnetic anisotropy energies due to the Co oxides that evolve into different oxide forms, which are characterized by micro-area X-ray absorption spectroscopy and X-ray photoelectron spectroscopy. The coercive field of the area pre-exposed to plasma can decrease to a value 10 Oe smaller than that unexposed to plasma, whereas after a longer duration of oxidation the coercive field can instead become larger in the area pre-exposed to plasma than that unexposed, leading to an opposite magnetic pattern. Various forms of oxidation can therefore provide an additional dimension for magnetic-domain engineering to the current conventional lithographies.

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Section: Methodssupporting

confidence: 85%

Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Dependence of magnetic domain patterns on plasma-induced differential oxidation of CoPd thin films

Wang,

Liu,

Chuang

et al. 2021

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“…Therefore, the first and second steps of the reversal in area A are attributed to the top partially oxidized layer and the bottom CoPd layer, respectively, as illustrated in Figure b. As plasma treatment and the follow-up oxidation can induce segregation and migration of some Co atoms in the film to form Co oxides on the surface, a thin layer of Pd-rich phase is established above the bottom CoPd layer underneath the oxides. ,, (The X-ray photoelectron spectroscopy depth profile of the film is provided in the Supporting Information.) Area C is much less oxidized than area A in the sense that the former has a much lower Co-oxide concentration and a much smaller oxidation depth into the film, exhibiting only one dominating reversal process ascribed to the bottom CoPd layer.…”

Section: Experimental Results and Discussionmentioning

confidence: 99%

Chirality-Induced Noncollinear Magnetization and Asymmetric Domain-Wall Propagation in Hydrogenated CoPd Thin Films

Wang

Pan

Liu

et al. 2022

ACS Appl. Mater. Interfaces

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Array-patterned CoPd-based heterostructures are created through e-beam lithography and plasma pretreatment that induces oxidation with depth gradient in the CoPd alloy films, breaking the central symmetry of the structure. Effects on the magnetic properties of the follow-up hydrogenation of the thin film are observed via magneto-optic Kerr effect microscopy. The system exhibits a strong vertical and lateral antiferromagnetic coupling in the perpendicular component between the areas with and without plasma pretreatment, and asymmetric domain-wall propagation in the plasma-pretreated areas during magnetization reversal. These phenomena exhibit evident magnetic chirality and can be interpreted with the Ruderman–Kittel–Kasuya–Yosida coupling and the Dzyaloshinskii–Moriya interaction (DMI). The sample processing demonstrated in this study allows easy incorporation of lithography techniques that can define areas with or without DMI to create intricate magnetic patterns on the sample, which provides an avenue toward more sophisticated control of canted spin textures in future spintronic devices.

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“…1(a), with a larger H c of 7.3 Oe. The EB of the FePd film can be attributed to the domain-pinning effect at the Pd-rich/FePd interface due to PMA in the top Pd-rich layer [47]. The Pd-rich layer has been created because of a mild oxidation of Fe, which removes some Fe from the upper part of the film to form oxides on the surface and therefore increases the Pd concentration near the top.…”

Section: A Characterization Of the Hysteresis Loopsmentioning

confidence: 99%

Exchange-bias dependent diffusion rate of hydrogen discovered from evolution of hydrogen-induced noncollinear magnetic anisotropy in FePd thin films

Wang,

Cheng,

Sheu

et al. 2021

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Hydrogenation-induced noncollinear magnetic anisotropy is observed from the evolution of the magnetic domains in FePd alloy thin films using magneto-optic Kerr effect (MOKE) microscopy. MOKE images reveal complicated competitions between different magnetic anisotropies during hydrogen diffusion into the film. An intriguing enhancement of the hydrogen diffusion rate due to the presence of an initial exchange bias induced by a high magnet field is thereby discovered, pointing to an additional scope of controllability of magnetic metal hydrides as potential future hydrogen sensing and storage materials.

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Plasma-induced magnetic patterning of FePd thin films without and with exchange bias

Cited by 6 publications

References 52 publications

Dependence of magnetic domain patterns on plasma-induced differential oxidation of CoPd thin films

Dependence of magnetic domain patterns on plasma-induced differential oxidation of CoPd thin films

Chirality-Induced Noncollinear Magnetization and Asymmetric Domain-Wall Propagation in Hydrogenated CoPd Thin Films

Exchange-bias dependent diffusion rate of hydrogen discovered from evolution of hydrogen-induced noncollinear magnetic anisotropy in FePd thin films

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