Anomalous in-plane coercivity behaviour in hexagonal arrangements of ferromagnetic antidot thin films

Salaheldeen, Mohamed; Vega, V.; Fernández, Antonio Maestro; Prida, V.M.

doi:10.1016/j.jmmm.2019.165572

Cited by 18 publications

(16 citation statements)

References 43 publications

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“…Secondly, a light multistep magnetization behaviour has been observed for S3 Py and S3 and S5 Co/Py bilayer antidot samples, as shown in figure 3. This multistep magnetic behaviour in S3 Py specimen is characteristic of a contribution of the OOP magnetic anisotropy component that comes from the magnetic signal of the inner wall of nanoholes (see figure 2(h)) and the strong interfacial exchange coupling between the two ferromagnetic materials, as reported in [6,8,[21][22][23]. For the Co/Py specimens, it is also present a hard/soft interfacial coupling accompanied by a complex magnetization reversal process and a strong pinning of magnetic domains wall movement [4,23,24].…”

Section: Resultssupporting

confidence: 55%

“…Due to the strong interfacial exchange coupling between the two ferromagnetic structures in Co/Py bilayers, the reduction of HC// and mr// is higher than the observed in the single magnetic layer thin films [22]. Regarding the INP coercive field, the antidot samples exhibit larger values comparing to the STF, which has been observed also in [8,24] and ascribed to the pinning effect of the holes. By increasing the antidot hole diameter, the in-plane coercivity increment reaches the maximum for S3 antidot arrays samples, in concordance with the results obtained from MOKE measurements (see figure 3 OOP magnetic anisotropy for Co/Py bilayer antidot samples can be ascribed to a strong interfacial exchange coupling between the two FM materials.…”

Section: Resultsmentioning

confidence: 86%

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Enhancement the perpendicular magnetic anisotropy of nanopatterned hard/soft bilayer magnetic antidot arrays for spintronic application

et al. 2020

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Development of perpendicular magnetic anisotropy (PMA) thin films is a requisite for many applications. In this work, we have illustrated the enhancement of the PMA of Hard (Co)/ Soft (Permalloy, Py) ferromagnetic bilayers by depositing them onto nanoporous anodic alumina membranes with different hole diameters varying in the range between 30 nm and 95 nm. A dramatic change in the hysteresis loops behaviour with hole size, D, and magnetic surface cover ratio parameters has been observed: (1) for samples with small antidot hole diameters, the in-plane (INP) hysteresis loops show single-step magnetic behaviour; (2) for D = 75 nm, the hysteresis loops of Co/Py and Py samples exhibit a multistep magnetic behaviour; (3) a decreasing coercivity in the INP hysteresis loops for antidot arrays samples with D > 75 nm has been detected as a consequence of the reduction of the in-plane magnetic anisotropy and the rising of the out-of-plane component. A crossover of magnetic anisotropy from the in-plane to out-of-plane for bilayer antidot samples has been observed for Co/Py ferromagnetic bilayers, favoured by the interfacial exchange coupling between the two ferromagnetic materials. These findings can be of high interest for the development of novel magnetic sensors and for perpendicular-magnetic recording patterned media based on template-assisted deposition techniques.

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Section: Resultssupporting

confidence: 55%

Section: Resultsmentioning

confidence: 86%

Enhancement the perpendicular magnetic anisotropy of nanopatterned hard/soft bilayer magnetic antidot arrays for spintronic application

et al. 2020

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“…This scenario agrees with the magnetic domain structure for the z component, in which PMSs are related to the head-to-head or tail-to-tail magnetic moment interaction. The enhancement of PMS for FM nanostructured thin film with W < 27 nm was detected and studied in detail in our previous work [ 31 , 33 , 64 ]. The strong induced PMS in the FM layer is stable enough to overcome the FM/AFM coupling between the layers, as there is no significant change in the PMS for AFM layers.…”

Section: Micromagnetic Simulationsmentioning

confidence: 99%

Enhancement of Exchange Bias and Perpendicular Magnetic Anisotropy in CoO/Co Multilayer Thin Films by Tuning the Alumina Template Nanohole Size

et al. 2022

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The interest in magnetic nanostructures exhibiting perpendicular magnetic anisotropy and exchange bias (EB) effect has increased in recent years owing to their applications in a new generation of spintronic devices that combine several functionalities. We present a nanofabrication process used to induce a significant out-of-plane component of the magnetic easy axis and EB. In this study, 30 nm thick CoO/Co multilayers were deposited on nanostructured alumina templates with a broad range of pore diameters, 34 nm ≤ Dp ≤ 96 nm, maintaining the hexagonal lattice parameter at 107 nm. Increase of the exchange bias field (HEB) and the coercivity (HC) (12 times and 27 times, respectively) was observed in the nanostructured films compared to the non-patterned film. The marked dependence of HEB and HC with antidot hole diameters pinpoints an in-plane to out-of-plane changeover of the magnetic anisotropy at a nanohole diameter of ∼75 nm. Micromagnetic simulation shows the existence of antiferromagnetic layers that generate an exceptional magnetic configuration around the holes, named as antivortex-state. This configuration induces extra high-energy superdomain walls for edge-to-edge distance >27 nm and high-energy stripe magnetic domains below 27 nm, which could play an important role in the change of the magnetic easy axis towards the perpendicular direction.

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“…Recently, Fe–Pd alloy nanostructure arrays based on self-assembling techniques have shown a strong potential for energy-assisted recording on nanoscale magnetic media, ultrafast spintronic technology and nano-actuators in biomedical applications [ 11 , 12 , 13 , 14 ]. For such applications, tailoring the direction and strength of the magnetic anisotropy, especially for the thermal stability and switching reliability of magnetic bits, is a crucial prerequisite [ 15 ]. In this regard, the existence of ordered arrays of nanoholes (i.e., antidot arrays) induces a demagnetization field distribution around the holes that can completely alter the magnetic properties of a non-patterned thin film, such as its switching field, magnetization reversal mechanism and intrinsic magnetic anisotropy [ 16 , 17 , 18 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Dependence of the Magnetization Process on the Thickness of Fe70Pd30 Nanostructured Thin Film

et al. 2020

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Fe–Pd magnetic shape-memory alloys are of major importance for microsystem applications due to their magnetically driven large reversible strains under moderate stresses. In this context, we focus on the synthesis of nanostructured Fe70Pd30 shape-memory alloy antidot array thin films with different layer thicknesses in the range from 20 nm to 80 nm, deposited onto nanostructured alumina membranes. A significant change in the magnetization process of nanostructured samples was detected by varying the layer thickness. The in-plane coercivity for the antidot array samples increased with decreasing layer thickness, whereas for non-patterned films the coercive field decreased. Anomalous coercivity dependence with temperature was detected for thinner antidot array samples, observing a critical temperature at which the in-plane coercivity behavior changed. A significant reduction in the Curie temperature for antidot samples with thinner layer thicknesses was observed. We attribute these effects to complex magnetization reversal processes and the three-dimensional magnetization profile induced by the nanoholes. These findings could be of major interest in the development of novel magnetic sensors and thermo-magnetic recording patterned media based on template-assisted deposition techniques.

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Anomalous in-plane coercivity behaviour in hexagonal arrangements of ferromagnetic antidot thin films

Cited by 18 publications

References 43 publications

Enhancement the perpendicular magnetic anisotropy of nanopatterned hard/soft bilayer magnetic antidot arrays for spintronic application

Enhancement the perpendicular magnetic anisotropy of nanopatterned hard/soft bilayer magnetic antidot arrays for spintronic application

Enhancement of Exchange Bias and Perpendicular Magnetic Anisotropy in CoO/Co Multilayer Thin Films by Tuning the Alumina Template Nanohole Size

Dependence of the Magnetization Process on the Thickness of Fe70Pd30 Nanostructured Thin Film

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