Preparation and Characterisation of Electrodeposited Ni–Cu/Cu Multilayers

Alper, Mürsel; Baykul, M. Celalettin; Péter, László; Tóth, J.; Bakonyi, I.

doi:10.1023/b:jach.0000035608.49948.e8

Cited by 35 publications

(21 citation statements)

References 19 publications

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“…It should be noted that a large GMR value can originate also from a strong SPM contribution due to a fragmentation of the magnetic layer which can be especially pronounced if both types of layers are fairly thin as reported for ED Ni-Cu/Cu mulitlyers. 22 The AMR magnitude is also indicated in Fig. 1b and it has a nearly constant value of about 0.5 % for all multilayers with GMR.…”

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

confidence: 76%

“…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%

“…The other majority of GMR results was obtained on ED Ni-Cu/Cu multilayers prepared from sulfate/sulfamate electrolytes in P/P mode. 9,10,14,16,17,[20][21][22]24 It appears from Table 5 of Ref. 6 that the applied Cu deposition potentials of these previous studies were either more positive (enabling a significant dissolution of Ni from the previously deposited magnetic layer) or more negative (promoting the codeposition of Ni into the non-magnetic layer) than the optimum potential range established in the present study for a sulfate/sulfamate bath (see the Experimental section) to exclude the above mentioned reactions during the Cu deposition cycle.…”

Section: Introductionmentioning

confidence: 99%

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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: 76%

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

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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

Fesharaki

Péter

Schucknecht

et al. 2012

J. Electrochem. Soc.

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“…Toth-Kadar et al (2000) experimented galvanostatic deposition to produce nickelcopper alloy deposit multilayer by employing DC and pulse current. Alper et al (2004) discussed the preparation and characterization of nickel-copper alloy multilayers and studied the effect of copper in the deposit with respect to giant magneto resistance (GMR). Ismail et al (2004) investigated electrochemical behaviour of nickelcopper alloy deposit with different nickel content in sulphamate electrolyte.…”

Section: Introductionmentioning

confidence: 99%

Nano-nickel–copper alloy deposit for improved corrosion resistance in marine environment

Silaimani

Vivekanandan

Veeramani

2014

Int. J. Environ. Sci. Technol.

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The nickel-copper alloy (70:30) prepared by metallurgical route is currently employed in marine environments because of its good resistance to corrosion. This alloy forms a thin protective surface layer when exposed to marine atmosphere and thus provides its corrosion resistance. Electrodeposition of nickel-copper alloy from sulphamate acetate-based electrolyte is a new and novel approach and was experimented. The detailed study was performed on the effect of electrolyte composition, current density and pH on the preparation of alloy deposit; the prepared alloy deposit particle size is of 78 nm, and the surface morphology of the alloy deposit was characterized with X-ray diffraction, scanning electron microscopy, EDAX, and atomic force microscope. Nickel-copper alloy deposited from the sulphamate acetate-based electrolyte operated at a temperature of 30°C, with a pH of 6.6 and at 3 A/dm 2 , produces nickelcopper (70:30) alloy deposit. The corrosion behaviour of this alloy deposit was studied by potentiodynamic polarization method; the corrosion current of nickel is 8.67 lA cm -2 and the nickel-copper alloy is 2.65 lA cm -2 .

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“…Como exemplo, pode-se citar as propriedades magnéticas de multicamadas de níquel e cobre (mais precisamente Ni/Cu e Cu). [10][11][12] Oscilações de corrente durante a eletrodeposição de cobre e estanho na presença de surfactante foram observadas recentemente. 2,5,9 O mecanismo geral associado ao aparecimento de oscilações durante a deposição de metais na presença de surfactantes é conhecido há algum tempo.…”

Section: Introductionunclassified

Co-eletrodeposição oscilatória de cobre e estanho

Joanni¹,

González²,

Varela³

2008

Quím. Nova

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Recebido em 17/9/07; aceito em 18/1/08; publicado na web em 20/8/08OSCILLATORY CO-ELECTRODEPOSITION OF COPPER AND TIN. It is investigated in the present contribution the oscillatory co-electrodeposition of CuSn on a polycrystalline gold surface in the presence of Triton X-100 surfactant and citric acid as additive, in acidic media. The experiments were conducted under potentiostatic control and the system dynamics characterized in terms of the morphology and stability of the current oscillations. Besides modulations in the frequency and amplitude of the current oscillations, several patterned states were observed, including relaxation-like and mixed mode oscillations. The oscillations were found to be very robust and some time series presented regular motions up to about two hours.Keywords: oscillations; electrodeposition; self-organization. INTRODUÇÃOA eletrodeposição de metais, ligas e óxidos metálicos em regime oscilatório tem sido objeto de vasta investigação nos últimos anos. [1][2][3][4][5][6][7][8][9] Em termos da morfologia dos depósitos formados, um aspecto interessante é a estruturação interfacial auto-organizada adjacente ao processo oscilatório. Além de questões fundamentais associadas a esses processos ainda não decifradas, tal estratégia de manipulação da arquitetura interfacial por meio de processos auto-organizadores se apresenta como muito promissora para a obtenção de materiais eletródicos com propriedades específicas. Vários eletrodepósitos obtidos através dessa metodologia têm propriedades específicas e, portanto, possuem lugar de destaque em algumas aplicações. Como exemplo, pode-se citar as propriedades magnéticas de multicamadas de níquel e cobre (mais precisamente Ni/Cu e Cu). 10-12Oscilações de corrente durante a eletrodeposição de cobre e estanho na presença de surfactante foram observadas recentemente.2,5,9 O mecanismo geral associado ao aparecimento de oscilações durante a deposição de metais na presença de surfactantes é conhecido há algum tempo.13,14 Em linhas gerais, a adsorção de surfactantes catiônicos compete por sítios superficiais com os cátions em solução na mesma faixa de potencial, gerando, por conseguinte, uma curva corrente (I) versus potencial ( ) em forma de "N", com sua correspondente resistência diferencial negativa (NDR, negative differential resistance). Mecanisticamente, tais sistemas são classificados como osciladores eletroquímicos do tipo N-NDR. Adicionalmente, o transporte de massa de espécies eletroativas à superfície do eletrodo pode contribuir como um ciclo de retro-alimentação negativa. Nesses termos, Nakato e colaboradores 5,9 discutiram os detalhes da dinâmica oscilatória do sistema Cu/Sn como dado a seguir. Considere-se inicialmente que o cobre é depositado em potenciais em torno de 300 mV menos negativo que o estanho. Devido à diferença de eletronegatividade, o estanho presente no co-depósito Sn-Cu encontra-se carregado positivamente e o cobre negativamente, de forma que a quantidade de surfactante catiônico adsorvido na superfície aumenta com o aumento...

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Preparation and Characterisation of Electrodeposited Ni–Cu/Cu Multilayers

Cited by 35 publications

References 19 publications

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

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

Nano-nickel–copper alloy deposit for improved corrosion resistance in marine environment

Co-eletrodeposição oscilatória de cobre e estanho

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