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We have already reported some electroplated magnetic films using aqueous solutions. In the present study, we proposed a fabrication process for electroplated soft magnetic films (Ni films) using gel electrolytes. We added gelatin to the plating baths and confirmed that adding 22 g/L of gelatin enabled us to obtain gel electrolytes. Using the gel electrolytes, we electroplated Ni films and evaluated their structural and magnetic properties. From the evaluation of magnetic properties, we confirmed spontaneous magnetization of the Ni films prepared from the gel electrolyte. For obtaining thick Ni films (>1 μm), we investigated stirring the gel electrolyte during plating. As a result, we found that stirring increased the thickness, and our result suggests that stirring the gel electrolyte is useful to increase the deposition rate. In our experimental conditions, the deposition rate of the plating process was ∼0.25 μm/min. From XRD analysis, the structure of Ni films for gel electrolytes was oriented in the fcc (220) plane and slightly different from that for liquid electrolytes. From these results, we found that soft magnetic films could be obtained from the gel electrolyte and that gel plating is one of the attractive fabrication processes of the thick films. [ABSTRACT FROM AUTHOR]

We prepared L10 ordered Fe50Pt50 thick-films on Cu substrates using the electroplating method and evaluated their high-temperature properties in the temperature range of 25-200°C. The Hc and the (BH)max at 150°C for the Fe50Pt50 films annealed by ordinary annealing method (700°C, 60 min) were 500 kA/m and 50 kJ/m3, respectively, and the thermal coefficient of Hc was -0.3%/°C. To improve the high-temperature properties, we employed a flash annealing method using an infrared furnace (8 kW). The flash annealing method improved the high-temperature properties (Hc = 700 kA/m, (BH)max = 70 kJ/m3 at 150°C) and the thermal coefficient (-0.21%/°C). The thermal stability of the films is comparable to those for Sm-Co-system magnets and better than for Nd-Fe-B-system ones. We, therefore, found the L10 ordered Fe50Pt50 films prepared by the electroplating and the flash annealing are one of the hopeful small magnets in the wide temperature range. [ABSTRACT FROM AUTHOR]

We prepared exchange-coupled Fe-Ni/Fe22Ni78 double-layered thick films ($24~\mu \text{m}$ in thickness) using an electroplating method and evaluated their soft magnetic properties. The total Fe content of the double-layered films was varied by the change in the Fe content in Fe-Ni layer, and the coercivity was evaluated. The double-layered films with the same layer thickness ($12~\mu \text{m}$ for Fe-Ni layer and $12~\mu \text{m}$ for Fe22Ni78 one) showed lower coercivity compared with the single-layered Fe-Ni films. To confirm the effect of the exchange coupling between both layers, we changed the layer thickness for the Fe22Ni78 magnetic phase from 1 to $12~\mu \text{m}$ , keeping at $24~\mu \text{m}$ of the total film thickness. The coercivity of the double-layered films was dramatically decreased with increasing the layer thickness of the Fe22Ni78 phase from 1 to $6~\mu \text{m}$. This result suggests that the exchange coupling works effectively to reduce the coercivity of the Fe-Ni phase when the Fe22Ni78 layer thickness is $> 6~\mu \text{m}$. Consequently, we increased the saturation magnetization without the increase in the coercivity and concluded that the use of the exchange coupling is one of the attractive methods to prepare soft magnetic materials with good magnetic properties. [ABSTRACT FROM AUTHOR]

Fe–Ni alloy films were prepared by electroplating in a plating bath containing a choline chloride and ethylene glycol-based deep eutectic solvent (DES). The Fe content of the electroplated films was found to vary from 0 at.% to 100 at.% and was dependent on the amount of Fe reagent in the plating bath. The composition of the electroplated films could be controlled easily by changing the composition of the bath. We observed bcc or fcc Fe–Ni crystalline phase in the electroplated films by X-ray diffraction and confirmed that magnetically soft Fe–Ni alloy films could be obtained from the DES-based bath. The current efficiency for the plating process was as high as >88% over a wide range of the Fe reagent concentrations. Therefore, we conclude that the DES is an attractive solvent for preparing the Fe–Ni alloy films. [ABSTRACT FROM AUTHOR]