Effect of interface number on giant magnetoresistance

Dulal, S.M.S.I.; Charles, E.

doi:10.1016/j.jpcs.2009.12.082

Cited by 12 publications

(6 citation statements)

References 23 publications

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“…In line with this, the saturation fields are much smaller than in any of the previously studied ED Ni-Cu/Cu multilayers for which MR(H) curves were reported at all. 9,14,15,[18][19][20][21][22][23]25,27,[29][30][31] This implies a superior quality of the present multilayers with respect to previous studies.…”

Section: Ni-cu/cu Multilayers With Varying Cu Layer Thickness (Series B)mentioning

confidence: 84%

Magnetoresistance and Structural Study of Electrodeposited Ni-Cu/Cu Multilayers

Fesharaki

Péter

Schucknecht

et al. 2012

J. Electrochem. Soc.

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-Electrodeposition was used to produce Ni-Cu/Cu multilayers by two-pulse plating (galvanostatic/potentiostatic control) from a single sulfate/sulfamate electrolyte at an optimized Cu deposition potential for the first time. Magnetoresistance measurements were carried out at room temperature for the Ni-Cu/Cu multilayers as a function of the Ni-Cu and Cu layer thicknesses and the electrolyte Cu 2+ ion concentration. Multilayers with Cu layer thicknesses above 2 nm exhibited a giant magnetoresistance (GMR) effect with a dominating ferromagnetic contribution and with low saturation fields (below 1 kOe). A significant contribution from superparamagnetic (SPM) regions with high saturation fields occurred only for very small nominal magnetic layer thicknesses (around 1 nm). The presence of SPM regions was concluded from the GMR data also for thick magnetic layers with high Cu contents. This hints at a significant phase-separation in Ni-Cu alloys at low-temperature processing, in agreement with previous theoretical modeling and experiments. Lowtemperature measurements performed on a selected multilayer down to 18 K indicated a strong increase of the GMR as compared to the room-temperature GMR. Structural studies of some multilayer deposits exhibiting GMR were performed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns of Ni-Cu/Cu multilayers exhibited in most cases clear satellite peaks, indicating a superlattice structure which was confirmed also by cross-sectional TEM. The deterioration of the multilayer structure revealed by XRD for high Cu-contents in the magnetic layer confirmed the phase-separation concluded from the GMR data.

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Section: Ni-cu/cu Multilayers With Varying Cu Layer Thickness (Series B)mentioning

confidence: 84%

Magnetoresistance and Structural Study of Electrodeposited Ni-Cu/Cu Multilayers

Fesharaki

Péter

Schucknecht

et al. 2012

J. Electrochem. Soc.

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“…While, the GMR value of the nanocylinder arrays, which were electrodeposited at E Co of −1.00 V, increased up to ~16%, as shown in Figure 8 c’. It has been reported that the GMR value increases as the number of interfaces between ferromagnetic and non-magnetic layers increases [ 29 ]. As shown in Figure 5 d, the Co layer thickness became thinner as the pulsed potential was shifted to a noble region.…”

Section: Resultsmentioning

confidence: 99%

Determination of Cobalt Spin-Diffusion Length in Co/Cu Multilayered Heterojunction Nanocylinders Based on Valet–Fert Model

2021

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Anodized aluminum oxide (AAO) nanochannels of diameter, D, of ~50 nm and length, L, of ~60 µm (L/D: approx. 1200 in the aspect ratio), were synthesized and applied as an electrode for the electrochemical growth of Co/Cu multilayered heterojunction nanocylinders. We synthesized numerous Co/Cu multilayered nanocylinders by applying a rectangular pulsed potential deposition method. The Co layer thickness, tCo, ranged from ~8 to 27 nm, and it strongly depended on the pulsed-potential condition for Co layers, ECo. The Cu layer thickness, tCu, was kept at less than 4 nm regardless of ECo. We applied an electrochemical in situ contact technique to connect a Co/Cu multilayered nanocylinder with a sputter-deposited Au thin layer. Current perpendicular-to-plane giant magnetoresistance (CPP-GMR) effect reached up to ~23% in a Co/Cu multilayered nanocylinder with ~4760 Co/Cu bilayers (tCu: 4 nm and tCo: 8.6 nm). With a decrease in tCo, (ΔR/Rp)−1 was linearly reduced based on the Valet–Fert equation under the condition of tF > lFsf and tN < lNsf. The cobalt spin-diffusion length, lCosf, was estimated to be ~12.5 nm.

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“…The increase can be explained by the fact that an increase in number of bilayers increases the number of interfaces, leading to more interface electron scattering and decreasing the shunting effect of the metallic conductive layer [10], and thus CPP-GMR increases. The decrease is ascribed to the gradual deterioration of the structure as the deposit grows; the multilayer interfaces are more significant at the beginning of the deposit than later.…”

Section: Resultsmentioning

confidence: 99%

“…One of the frequently used fabrication methods of the high-aspect-ratio multilayered nanowires is the electrodeposition technique due to its simplicity, convenience, and cost-effectiveness compared to the other preparation techniques that have been employed such as chemical vapor deposition, molecular beam epitaxy, and magnetron sputtering [5][6][7][8]. So far, great efforts have been devoted to the research on the CPP-GMR of CoNi/Cu [9][10][11], NiFe/Cu [12][13][14], and Co/Cu [7,[15][16][17] multilayered nanowires and it has been shown that the GMR and the magnetic properties of multilayer nanowire arrays are affected by a variety of factors, including the structure of the materials, wire diameter, wire total length, composition, layer thickness, and other factors. However, only few studies have systematically investigated the effects of the period number and copper layer thickness on the magnetic properties and the CPP-GMR [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Perpendicular Giant Magnetoresistance and Magnetic Properties of Co/Cu Nanowire Arrays Affected by Period Number and Copper Layer Thickness

Han

Qin

Quan

et al. 2016

Advances in Condensed Matter Physics

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One-dimensional magnetic nanowires have attracted much attention in the last decades due to their unique physical properties and potential applications in magnetic recording and spintronics. In this work, ordered arrays of Co/Cu multilayered nanowires which can be exploited to develop magnetoresistive sensors were successfully prepared using porous anodic alumina (PAA) templates. The structure and morphology of the multilayered nanowire arrays were characterized by transmission electron microscopy and scanning electron microscopy. The nanowire arrays are highly ordered and the average diameter is about 50 nm, which is controlled by the pore diameter of the PAA templates. The influences of period number and Cu layer thickness on the magnetic and the giant magnetoresistance (GMR) properties were investigated. The coercivity and remanence ratio increase first and then gradually tend to be stable with the increase of period number and the Cu layer thickness, while the GMR ratio increases first and then decreases with the increase of the period number accompanied by an oscillatory behavior of GMR as the Cu layer thickness changes, which are ascribed to the spin dependence electron scattering in the multilayers. The optimum GMR of −13% appears at Co (50 nm)/Cu (5 nm) with 200 deposition cycles in our experimental conditions.

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Effect of interface number on giant magnetoresistance

Cited by 12 publications

References 23 publications

Magnetoresistance and Structural Study of Electrodeposited Ni-Cu/Cu Multilayers

Magnetoresistance and Structural Study of Electrodeposited Ni-Cu/Cu Multilayers

Determination of Cobalt Spin-Diffusion Length in Co/Cu Multilayered Heterojunction Nanocylinders Based on Valet–Fert Model

Perpendicular Giant Magnetoresistance and Magnetic Properties of Co/Cu Nanowire Arrays Affected by Period Number and Copper Layer Thickness

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