Anisotropic structural and magnetic properties of arrays of Fe26Ni74 nanowires electrodeposited in the pores of anodic alumina

Khan, H.R.; Petrikowski, K.

doi:10.1016/s0304-8853(00)00209-2

Cited by 76 publications

(39 citation statements)

References 16 publications

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“…The easy axis coercivity, H ce,, obtained with the thin films is about 25-120 times lower than the easy axis coercivity, H c , parallel, in nanowire arrays. It is important to note, that in the studies of magnetic properties of NiFe nanowires [13][14][15][16][17][18][19][20] a magnetocrystalline anisotropy was taken into consideration as very small or "negligible"-which is true if one compares with the values of K sh and K mc . However, although the K me is larger than K mc , the magnetoelastic, K me , anisotropy of NiFe nanowires-obtained and measured at the room temperature-was completely ignored.…”

Section: Magnetic Properties Of Nife Nanowire Arrays With 8-55%fe-mentioning

confidence: 99%

Anomalous Codeposition offccNiFe Nanowires with 5–55% Fe and Their Morphology, Crystal Structure and Magnetic Properties

Dragos

Chiriac

Lupu

et al. 2015

J. Electrochem. Soc.

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The electrodeposition of NiFe nanowires-with the length ∼3.0 μm and diameter 200 nm-using the porous anodized aluminum oxide (AAO) templates on the sputtered Au-back electrode (300 nm) using sulfate/chloride electrolyte solution and potential pulsed deposition. The electrode area of Au-AAO template, determined by the reversible one-electron transfer oxidation of K 4 Fe(CN) 6 , used as a probe in CV, was found to be ∼2.4 times larger than Au-thin film electrode. The anomalous codeposition phenomenon known as a ,,volcano" type curve-with a maximum in Fe-content in NiFe as a function of the applied potential-was observed in the literature. The observed results were explained through the limited mass transport of Fe +2 ions after the peak. This explanation is partially correct, but not complete. The electrodeposition of NiFe nanowire in this work resulted in a similar "volcano" type curve. The alternative explanation of anomalous codeposition-through the surface concentration of H + dependent adsorption/desorption of FeOH + and NiOH + electroactive species-was proposed. The electrodeposition of NiFe nanowire arrays using a designed pulse potential method produced fcc NiFe nanowires with 5-55% Fe with controlled composition, length, and uniformity.The distinct decrease of parallel coercivity of NiFe nanowire arrays having the same length was observed with increase of Fe-content in NiFe, which also correlates with the increase of their magnetic saturation. 12 The studies on magnetic properties of NiFe nanowire arrays were intensified during last 15 years. [13][14][15][16][17][18][19][20] The electrodeposition of NiFe alloys exhibits a phenomenon known as an anomalous codeposition, which is characterized by the anomaly that less noble metal, i.e. Fe, deposits preferentially. 21 The extent of anomalous codeposition can be evaluated by the "selectivity ratio" (SR), which is defined as an atomic ratio of Fe/Ni in the deposit to the molar ratio of Fe +2 /Ni +2 in the electrolyte. 22 The SR is dependent on solution condition (pH, presence of organic additives, concentration of electrolytes, temperature, etc), method of electrodeposition (constant current density, controlled potential, pulsed current or potential), and the thickness of deposit. The value of SR ranges from 1.0 (for non-anomalous codeposition) to 15 (for anomalous codeposition). The variation of composition of NiFe films affects the following properties of deposit: (i) stress, 23 (ii) magnetostriction, 24 (iii) crystal structure, 25 and (iv) grain size. 26 Thereby, the resulting changes profoundly influence the magnetic behavior of electrodeposited NiFe alloys, which was demonstrated recently. 27The present work describes the method of electrodeposition of NiFe nanowires into anodized aluminum oxide (AAO) templates with the controlled elemental composition using designed potential pulse electrodeposition. We report here a new explanation for the observed anomalous codeposition of NiFe in nanowires, through the surface concentration of H + dependent adsorption/...

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Section: Magnetic Properties Of Nife Nanowire Arrays With 8-55%fe-mentioning

confidence: 99%

Anomalous Codeposition offccNiFe Nanowires with 5–55% Fe and Their Morphology, Crystal Structure and Magnetic Properties

Dragos

Chiriac

Lupu

et al. 2015

J. Electrochem. Soc.

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show abstract

“…These arrays of ferromagnetic nanowires prepared by this technique show distinct magnetic properties, e. g., easy axis of magnetization perpendicular to the substrate plane, enhanced coercivity (H c ), and remanent magnetization (M r / [64]. The fabrication of nanowire arrays of Co, FeNi, and Ni by electrochemical deposition in the pores of anodic alumina and their structural and magnetic properties [65][66][67] has been reported. These ferromagnetic nanodisks or wires have a potential of applications such as high-density recording media and sensors, e. g., reading heads in computers or high-sensitivity micromagnetic sensors.…”

Section: Nanostructured Nanocomposites Films Of Co and Cofementioning

confidence: 99%

Nanoparticle Films

Khan¹

2015

Handbook of Thin-Film Technology

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“…By the analysis of magnetic properties, they observed higher coercivity of 84349.5 A/m and higher Mr/Ms compared to a body material. Soft magnetic Fe 26 Ni 74 NWs of 18 nm diameter and various lengths, electrodeposited in the pores of anodic alumina, were synthesized by Khan et al (Khan & Petrikowski, 2000), who made a depth research on its properties such as the room temperature magnetization, magnetoresistance and structural properties. NWs show perpendicular magnetic anisotropy, anisotropic crystallographic and magnetoresistance behavior with a coercivity of 967 Oe and a remanence value of 85%, and it should be noted that an electrodeposited Fe 26 Ni 74 layer (6 μm) on a copper substrate shows in-plane anisotropy and a coercivity of less than 1 Oe.…”

Section: Ferromagnetic Alloys 441 Fe-nimentioning

confidence: 99%