Ultrasoft and High Magnetic Moment CoFe Films Directly Electrodeposited from a B-Reducer Contained Solution

Abstract

A methodology to fabricate ultrasoft CoFe nano-/microfilms directly via electrodeposition from a semineutral iron sulfate solution is demonstrated. Using boron-reducer as the additive, the CoFe films become very soft with high magnetic moment. Typically, the film coercivity in the easy and hard axes is 6.5 and 2.5 Oersted, respectively, with a saturation polarization up to an average of 2.45 Tesla. Despite the softness, these shining and smooth films still display a high-anisotropic field of ~45 Oersted with permeability up to 104. This kind of films can potentially be used in current and future magnetic recording systems as well as microelectronic and biotechnological devices.

Electrodeposition of granular FeCoNi films with large permeability for microwave applications

“…2 In our previous work, high B s and low H c films were obtained using the organic B-reducer as an additive in the plating solution. 33 However, the resultant films were verified to have a relatively low resistivity (<10 À5 U cm), making them unsuitable for microwave applications in the high frequency (GHz) range. 2 Hence in this work, FeCoNi films were electrodeposited using different organic and inorganic additives in the plating solution.…”

“…25 It is also an effective additive for uniform deposition by reducing the particle size of the deposited film and improving the potential of the cathode (substrate) via cathode polarization. 33 By optimizing the concentration of B-reducer and the plating parameters, very magnetically soft FeCoNi films with high B s were prepared. In order to obtain both high B s and low H c values, larger atomic ratios (40-60%) of Fe (B s ¼ 2.2 T) 1,22 and Co (B s ¼ 1.8 T), and lower ratio (1-5%) of Ni (B s ¼ 0.6 T) in the films were maintained by using the optimized salt concentrations and the current density range (12-35 mA cm À2 ).…”

Influence of the Electrodeposited Co-Fe Alloys’ Characteristics on their Magnetic Properties

“…For examples, relatively high saturation magnetization of 24 kG and fairly low coercivity of 9 Oe was achieved by electrodeposited CoFe films as investigated by Osaka et al [2,4]. Zong et al developed electrodeposited CoFe films with boron doping that exhibited low coercivity of 6.5 Oe in easy direction and 24.5 kG saturation magnetization [7]. While soft magnetic films could be fabricated by several techniques [1,2], by far, electrodeposition stands as one of the most attractive processing routes, owing to ease of production, low cost, and its ability to precisely control a film thickness.…”