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The recent trend of increasing the density of magnetic recording devices requires a write head core material with a higher saturation magnetic flux density, Bs, and a lower coercivity, Hc, than can be obtained with the conventional Permalloy (NiFe) film. To meet this demand, we recently developed a process of forming a CoNiFe ternary alloy film by electrodeposition, which satisfies the requirement for the write head core to be used in high magnetic recording density devices of the next generation. 1-4 During this development work involving an investigation of effects of various organic additives, it was observed that saccharin and thiourea, both of which contain sulfur, behave very differently from each other in the electrodeposition of CoNiFe alloy. Namely, with saccharin the inclusion of sulfur is limited at approximately 0.3 atom % with increasing concentration in the bath, and magnetically soft CoNiFe films with low Hc can be obtained only in the region of alloy composition where Bs is low. 5 With thiourea, on the other hand, the sulfur inclusion increases linearly with its concentration, yielding a film with desirable magnetic properties (high Bs and low Hc) at the sulfur content of approximately 0.6 to 0.9 atom %. 3 To understand the cause of the difference in behavior between saccharin and thiourea, we compared the structures of the adsorbed layers of the two different compounds on the surface of Au(111) by using scanning tunneling microscopy (STM). A fundamental difference was observed in the nature of adsorption between the two adsorbates.Both saccharin and thiourea have long been known as additives for nickel electroplating baths. The available body of knowledge on the mechanism of sulfur inclusion into nickel deposit was compared with the experimental results obtained with the CoNiFe system. Experimental The compositions and operating conditions of the baths used to plate CoNiFe alloy are shown in Table I. The electroplating was done using a rotating disk electrode (RDE) system. The substrate was a circular plate of borosilicate glass with a diameter of 10 mm, one side of which was coated with sputtered Cr (30 nm) and Permalloy (110 nm) films. The back and the side of this plate were coated with conducting silver paste to form a contact between the sputtered films and the shaft of the RDE. Magnetic properties of the electroplated films, 1.5 m thick, were measured, without removal from the substrates, by using a vibrating sample magnetometer. The sulfur content of the film was determined by an X-ray fluorescence (XRF) method, which was calibrated against the standard combustion method using LECO carbon-sulfur analyzer model CS-444LS.The STM investigation was performed on an Au(111) facet produced on a gold bead, which was prepared by the well-established method 6-8 consisting of annealing one end of a pure gold wire, 0.8 mm in diam, in a hydrogen-oxygen flame and quenching it in hydrogen-saturated pure water. The electrolyte used was 0.05 M HClO 4 , which was prepared by diluting concentrated ultrapure ...

A highly durable SiOC composite anode was prepared for use in lithium secondary batteries. The SiOC composite was synthesized by electrodeposition of SiCl 4 . The composite anode delivered a discharge capacity of 1045 mA h per gram of Si at the 2000 th cycle and 842 mA h per gram of Si even at the 7200 th cycle. The reason for the excellent cyclability was investigated by methods including field emission scanning electron microscopy (FESEM), scanning transmission electron microscopy with an energy dispersive X-ray analyser (STEM-EDX), and X-ray photoelectron spectroscopy (XPS). The results revealed that the excellent cyclability was achieved by the homogeneous dispersion of SiO x and organic/ inorganic compounds at the nanometre scale. The structural uniformity of the SiOC composite is believed to have suppressed the crack formation attributable to the stress resulting from the reaction of silicon with lithium during charge-discharge cycles.

A CoFe binary alloy film with 24 kG of saturation magnetic flux density, B s , was prepared by electrodeposition. The B s value of the CoFe alloy film prepared by electrodeposition from the conventional bath is usually equal to 21 kG. With the addition of trimethylamineborane, a well-known reducing agent, the B s value was found to increase to 23 kG. Furthermore, with the use of a separated compartment dual cell system, a B s value as high as 24 kG was reached. For obtaining the highest B s , it was found to be essential to avoid the oxidation of ferrous ion to ferric ion in the plating bath. The coercivity, H c , values were 15, 14, and 15 Oe for the films with 20, 23, and 24 kG of B s , respectively. The key for obtaining high B s materials is to avoid the oxidation of ferrous ions in the bath. In addition, it was found that the H c value of 15 Oe for CoFe film with the highest B s value of 24 kG could be lowered to 8 Oe by annealing in an applied magnetic field of 500 Oe.To meet the strong demand for high performance write-heads to be used for high density magnetic recording, 1 soft magnetic materials with high saturation magnetic density, B s , are being developed by many researchers. 2-6 We previously developed a CoNiFe alloy with B s ϭ 20-21 kG using electrodeposition 7,8 and it has been in practical use. The CoFe binary alloy is known as a material with B s of about 24 kG, which is close to the limiting value achievable with ferromagnetic alloys. 9 Several soft magnetic thin films with the highest B s value of 24 kG have recently been prepared by using a dry sputtering process, e.g., NiFe/CoFe-N/NiFe trilayer film, 10-12 CoFe-O granular film, 13 and CoFe-Al-O granular film. 14,15 However, thin films containing only Co and Fe do not exhibit soft magnetic properties. 16 On the other hand, the technique of electrodeposition is useful as an industrial process, and write-head cores are now being fabricated by electrodeposition. Thus, electrodeposited soft magnetic thin films of CoFe binary alloy with the highest B s value of 24 kG are now in strong demand.We have succeeded in preparing soft magnetic materials of CoFe binary alloy film with B s ϭ 24 kG by electrodeposition. 17 The key requirement for obtaining the high B s CoFe material in this binary alloy system is the prevention of oxidation of ferrous ion, Fe 2ϩ , to ferric ion, Fe 3ϩ , in the plating bath. In this paper, we discuss this key issue in fabricating the soft magnetic material with B s ϭ 24 kG. ExperimentalBinary CoFe alloy films were electrodeposited using a rotating disk electrode ͑RDE͒ system, in which the anode was made for Pt and the electrodeposited substrate was removable to determine properties of the electrodeposited film. The thickness of the electrodeposited alloy films was about 0.7 m. The substrate was a circular glass plate with a diam of 10 mm, coated with sputtered NiCr ͑5 nm͒ and NiFe ͑100 nm͒ films, and a Cu foil with a diam of 10 mm and a thickness of 8 m. The plating bath composition and operating conditions are shown in Table...

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Mesostructured Ni and Co particles are formed by metal deposition in the aqueous domains of lyotropic liquid crystals (LLC) using different reducing agents. We have investigated the role of reducing agents in metal deposition for the synthesis of highly-ordered mesoporous metals by electroless deposition. Slow metal deposition accompanied by the autocatalytic reaction of dimethylamineborane (DMAB), caused by the combination of Ni and DMAB, led to the formation of highly-ordered mesostructured Ni.

In order to solve the problem of polysulfide dissolution into the electrolyte on sulfur-based cathodes, we propose a novel method of modifying the S cathode by coating it with a polypyrrole (PPy) film, which is prepared by oxidative electropolymerization using a solution consisting of, 1-methyl-1-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and pyrrole. The PPy film demonstrates a high Li + transport number. The film