The effect of Fe3+ on magnetic moment of electrodeposited CoFe alloys—Experimental study and analytical model

Brankovic, Stanko R.; Bae, Sang-Eun; Litvinov, Dmitri

doi:10.1016/j.electacta.2008.03.071

Cited by 35 publications

(31 citation statements)

References 21 publications

(48 reference statements)

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“…The magnetic moment of Co 40-44 Fe 60-56 films starts to decrease for Fe 3 þ concentration that is very close to the calculated value of ½Fe 3 þ * i . This indicates correlation between the decrease of B s and necessary conditions for Fe(OH) 3 precipitation at the electrode-solution interface [35]. These data also show that the increase of ½Fe 3 þ beyond the calculated value of ½Fe 3 þ * i results in significant reduction of B s ($40%).…”

Section: Relation Between Surface Concentration Of H þ and Concentratsupporting

confidence: 63%

“…For illustration purposes, estimates of ½Fe 3 þ * i and ½Fe 3 þ * 1 for parameters and solution design for electrodeposition of 2.4-T CoFe alloys are presented in the table in Figure 27.4 [35]. In order to illustrate the effect of Fe 3 þ in plating solution on the properties of electrodeposited magnetic alloys, the B s measurements of Co 40-44 Fe 60-56 films for different Fe 3 þ concentrations in the plating bath are shown in Figure 27.4.…”

Section: Relation Between Surface Concentration Of H þ and Concentratmentioning

confidence: 99%

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Applications to Magnetic Recording and Microelectronic Technologies

Brankovic¹,

Vasiljević²,

Dimitrov³

2010

Modern Electroplating

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Early applications of electrodeposition in manufacturing were mainly confined to situations where relatively thick polycrystalline metal deposits were needed. These included protective or sacrificial metal layers for corrosion protection, decorative applications, and situations where metal coatings with specific mechanical properties were needed [1]. However, development of theoretical foundations in electrochemical engineering and electrometallurgy and the sophistication of the tools used for electrodeposition have contributed to widespread electrodeposition in high-tech industry where more rigorous thickness control of the deposit is required. Nowadays, electrodeposition is recognized as a mature deposition method for the fabrication of magnetic thin-film heads [2, 3] and in microelectronics and microelectromechanical system (MEMS) technologies [4][5][6][7]. The most recent developments suggest that electrodeposition is an attractive fabrication process for many emerging fields of nanotechnology. These new applications make the future of electrodeposition research a seemingly interesting and quite exciting endeavor.In this chapter we will review the most important electrodeposition processes used for fabrication of magnetic recording heads and in microelectronics technology. The most important parameters, criteria, and phenomena controlling the deposit morphology and properties are highlighted and discussed using the examples from the authors' own work and from the work of other prominent groups around the world. MAGNETIC RECORDINGNowadays electrodeposition is used for the fabrication of many important parts of magnetic recording heads, including magnetic shields and poles, Cu coils, and for connecting Cu studs, leads and pads, Au interconnects, and nonmagnetic gaps and coatings. Some of these electrodeposition processes and bath chemistries were adopted from other technologies as a common practice. However, the fabrication of the writing pole in magnetic recording heads has been the most important manufacturing step where electrodeposition has gained its fame as a cost-effective, reliable, and high-throughput operation (Fig. 27.1a). Over the years, the development of magnetic reader technologies, recording medias and the geometry of the magnetic recording process have posed many challenges that electrodeposition had to meet in order to stay competitive with other deposition methods. The common requirement for the alloys for magnetic pole fabrication is that they have low coercivity (softness), low magnetostriction (l % 0), and relatively high magnetic moment. The electrodeposition process of these alloys has to be scalable with high-throughput manufacturing with minimum effort in process control and reproducibility. The bath chemistry has to be stable over the time and compatible with other materials and processes used in through-mask fabrication.In the very beginning, the electrodeposited magnetic alloy for magnetic pole application was Ni 81 Fe 19 -Permalloy (inductive read heads)-with saturation magnetic fl...

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Section: Relation Between Surface Concentration Of H þ and Concentratsupporting

confidence: 63%

Section: Relation Between Surface Concentration Of H þ and Concentratmentioning

confidence: 99%

Applications to Magnetic Recording and Microelectronic Technologies

Brankovic¹,

Vasiljević²,

Dimitrov³

2010

Modern Electroplating

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“…First, there are always Fe +3 ions present in electrolyte solution due to the oxidation of Fe +2 either by oxygen dissolved in solution, or by oxidation at the anode. It was found that a critical concentration of Fe +3 >1.2 mM in solution results in a dramatic decrease of B s value of CoFe alloy by ∼44%, 28 due to the accumulation of Fe-oxides at the grain boundaries. The oxygen content in a CoFe deposit must stay below a critical value of 1-3 at.…”

mentioning

confidence: 99%

“…% in order to achieve a high saturation magnetization. [28][29][30][31] In industrial electrodeposition of 2.4 T CoFe films the problem of accumulation of Fe +3 ions in solution is solved by continues chemical reduction of Fe +3 to Fe +2 ions. In laboratory preparation of CoFe nanowire arrays ascorbic acid can be used as a reducing agent for Fe +3 ions, [15][16][17][18][19][20][21][22][23][24][25][26][27] and this will be discussed later in the text.…”

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Controlled Electrodeposition and Magnetic Properties of Co₃₅Fe₆₅Nanowires with High Saturation Magnetization

Ghemes

Dragos-Pinzaru

Chiriac

et al. 2016

J. Electrochem. Soc.

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Among all transition metals magnetic alloys, Co 35 Fe 65 possesses the highest saturation magnetization B S = 2.45 T at room temperature given by the so-called "Slater-Pauling limit". For controlled electrodeposition of Co 35 Fe 65 nanowire arrays the following parameters were found to be optimal: electrolyte solution with 1-2 mM malonic acid (MA), ionic ratio Fe +2 /Co +2 = 2.0, growth rate, and pulsed potential deposition with time-on (2.5 s) at the potential of −1.15 V/SCE and time-off (1.0 s) at −0.70 V/SCE. These arrays were deposited inside anodic aluminum oxide (AAO) templates that contained columnar nanopores with diameters either 35 or 200 nm. Cyclic voltammetry was used in solution with and without MA and reaction mechanism was proposed to explain the critical role of MA in electrodeposition of CoFe alloys. In addition to uniform deposition of stechiometric Co 35 Fe 65 alloys, a selectivity ratio, (SR) ∼1.0, were achieved, which means that the atomic ratio of Fe/Co in the nanowire matched the molar ratio of Fe +2 /Co +2 in the electrolyte. The magnetic behavior of the subsequent 2.45 T Co 35 Fe 65 nanowire arrays showed that the shape and magnetostatic anisotropies dominated the effective anisotropy, and the impact of magnetocrystalline and magnetelastic anisotropies field was very small. 1 The highest saturation magnetization of all transition-metal (TM) alloys at room temperature shows Co 36 Fe 65 alloy with respective saturation magnetization of B s = 2.45 T, which is commonly referred to us as the "Slater-Pauling limit".2 Thin films of these alloys, obtained either by electrochemical deposition (ED) or called sputter deposition, are currently used in high areal recording density (HRD) heads including longitudinal (LMR), perpendicular (PMR), and heat assisted (HAMR) magnetic recording. In fact, about 15 years ago Seagate Technologies was first in the recording head industry to introduce 2.4 T CoFe as the longitudinal writer pole material-which was fabricated by electrodeposition. 3 The advantages of electrochemical vs. sputtering deposition include reduced process content, reduced variance and reduced cost. Importantly, controlled electrodeposition is possible even into high aspect ratio of templates including anodized aluminum oxide-AAO, diblock copolymers-DBC, carbonate membranes, and porous silicone. Porous AAO templates are particularly attractive since the pore diameters can be 10-300 nm with pore densities in the range of 10 9 to 10 11 cm −2 . 4 Ferromagnetic nanowire arrays have been used as a miniaturized devices in electronics and optics. 5 In addition, such nanowires have a promising biomagnetic applications like biosensing, cell separation, MRI contrast agents and magnetic hyperthermia. [6][7][8][9][10] Most biomagnetic studies have been limited to nanometer iron-oxide based nanoparticles for MRI imaging and magnetic hyperthermia.6 However, the low saturation magnetization of the bulk iron-oxides (e.g. B s ∼0.5 T for Fe 2 O 3 11 ) prevents them from becoming highly efficient in hypertherm...

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“…In the above expression, the first term R 0 [mol⋅cm The corresponding coverage of saccharine is calculated using equation [6] and shown on the right ordinate. Solution details are presented in Table I.…”

Section: Saccharin Adsorptionmentioning

confidence: 99%

Critical Parameters of Solution Design for Electrodeposition of 2.4 T CoFe Alloys

et al. 2009

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The electrodeposition of soft, high magnetic moment alloys has become the critical fabrication step in manufacturing of magnetic recording heads. The need for ultimately high magnetic moment alloys (2.4 T CoFe) and the electrodeposition process capable of delivering magnetic structures with dimension in the range of several tens of nanometers are the new tasks that have to be addressed if the future magnetic recording devices will use the electrodeposited alloys for writing pole application. This complex challenge could be successfully achieved by fully considering the conditions at the electrochemical interface for additive adsorption and incorporation, iron hydroxide formation and incorporation, and by careful design of the bath chemistry and deposition parameters that would yield the high moment alloys with the optimum magnetic properties. In this manuscript, some of the key aspects of successful electrodeposition of 2.4 T CoFe alloys are discussed with experimental results and theoretical foundations indicating future direction for development of electrodeposited high moment alloys and nanostructures.

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The effect of Fe3+ on magnetic moment of electrodeposited CoFe alloys—Experimental study and analytical model

Cited by 35 publications

References 21 publications

Applications to Magnetic Recording and Microelectronic Technologies

Applications to Magnetic Recording and Microelectronic Technologies

Controlled Electrodeposition and Magnetic Properties of Co₃₅Fe₆₅Nanowires with High Saturation Magnetization

Critical Parameters of Solution Design for Electrodeposition of 2.4 T CoFe Alloys

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The effect of Fe3+ on magnetic moment of electrodeposited CoFe alloys—Experimental study and analytical model

Cited by 35 publications

References 21 publications

Applications to Magnetic Recording and Microelectronic Technologies

Applications to Magnetic Recording and Microelectronic Technologies

Controlled Electrodeposition and Magnetic Properties of Co35Fe65Nanowires with High Saturation Magnetization

Critical Parameters of Solution Design for Electrodeposition of 2.4 T CoFe Alloys

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Controlled Electrodeposition and Magnetic Properties of Co₃₅Fe₆₅Nanowires with High Saturation Magnetization