Soft magnetic granular material Co–Fe–Hf–O for micromagnetic device applications

Abstract

A granular magnetic material, Co–Fe–Hf–O, has been developed-using dc pulsed magnetron reactive sputtering. The deposition rate is as high as 1.3nm∕s. The electrical and magnetic properties of Co–Fe–Hf–O film can be tuned by changing O2 during deposition. A highly resistive, magnetically soft film has been achieved in a small range of the O2∕(Ar+O2) gas flow ratio. The origin of the dependence of magnetic and electrical properties of this material is studied and explained by monitoring the evolution of the film microstructure, using x-ray diffraction and transmission electron microscopy.

High-frequency magnetic characteristics of Fe-Co-based nanocrystalline alloy films

“…Important progresses in high-frequency soft magnetic materials have also been attained in composite granular films, in which Ferich crystalline nanoparticles are embedded in a nonmagnetic insulator matrix, such as Al 2 O 3 [8], ZrO 2 [11], HfO 2 [12,13], SiO 2 [14] and Si 3 N 4 [15]. However, large magnetization and high resistivity can not be simultaneously achieved because high electrical resistivity always comes out in these films at the expense of the saturation magnetization.…”

High frequency characteristics of soft magnetic Fe–O alloy thin films fabricated by helicon plasma sputtering

“…To overcome these difficulties and increase the efficiency of micromagnetic devices, a number of approaches have been taken and developed. Important progresses have been attained by granular metal/insulator composites, in which Fe-rich crystalline nanoparticles with high magnetic moments are embedded in a nonmagnetic insulator matrix, such as Al 2 O 3 [11], ZrO 2 [4], or HfO 2 [5,12]. However, soft magnetic properties, large magnetization, and high * Corresponding author.…”

“…There is a growing demand of magnetic thin film materials for high-radio-frequency (GHz) use: magnetic recording heads, integrated thin-film inductors, and electromagnetic noise absorbers [1][2][3][4][5][6]. In integrated inductors, ferromagnetic thin film materials can be incorporated in the inductors to boost their inductance and enhance their quality factor [7].…”

High-resistivity nanogranular Co–Al–O films for high-frequency applications

“…Their deposition either demands sophisticated multiple-target sputtering equipment, 9 making them less attractive for mainstream integrated circuit use due to the high cost, or relies on less accurately controlled processing, e.g., deposition with varied gas flow, impeding the realization of films with very high resistivity. 8 In this paper we present a study on pulsed dc reactive sputtering of Co 72 Al 28 in an ambient with fixed concentration of 20% oxygen. Deposition power is used as the control parameter defining the oxygen content ͑and thus resistivity͒ of the sputtered film.…”

“…[7][8][9][10][11] Nano/micro granular Ni-Fe films have been shown to yield high resistivities, 7 but this comes at the costs of a rather low permeability and poor control of granular nucleation during film deposition. Other granular films reported in the literature mostly consist of complicated processing involving nonconductive elements.…”