Reduction of magnetic damping and isotropic coercivity and increase of saturation magnetization in Rh-incorporated CoIr system

Abstract

Replacing Ir with Rh in a CoIr system possessing negative uniaxial magnetocrystalline anisotropy (K ) substantially reduces its magnetic damping and coercivity by more than half while retaining its high negative K . Moreover, a higher saturation magnetization (M ) and more isotropic coercivity are achieved. Such material development makes it particularly suitable for use as the soft underlayer (SUL) of magnetic recording media for reducing noise, and as the oscillation layer of a spin-torque oscillator (STO) for achieving higher oscillation frequency, larger AC magnetic field and lower driving current, which can be readily integrated with the current recording head for microwave-assisted magnetic recording. Finally, we recommend a composite free layer by coupling CoIr with a spin polarizer (Co or Co/Cu/Co) for the enhancement of the spin-polarization rate and, therefore, the improvement of STO efficiency. These could pave the way for CoIr-based materials to be implemented in devices requiring a negative K with low damping and high 'softness', such as oscillators.

Influence of additives on the magnetic damping constant of CoIr soft magnetic thin films with negative magnetocrystalline anisotropy*

“…[15,16] Recently, the reduction of magnetic damping constant in Rh-incorporated CoIr system has been reported. [17] It is also reported that the doping elements B [18] and SiO 2 [19] have an effect on soft magnetic properties of CoIr system. To understand the effects on the damping constant and gain control of the magnetic damping behavior, we prepared oriented hcp-CoIr thin films with different additives of B, Ni, and SiO 2 .…”

Gyromagnetic ratio of oriented hcp Co1−x Ir x soft magnetic films

“…Among the known soft magnetic films, close-packed hexagonal (hcp) CoIr films with grains that have a c-axis perpendicular to the film plane are a type of soft magnetic material with high easy-plane magnetocrystalline anisotropy energy that have been attracting special research interest. They are proven to be effective in increasing f r without decreasing the high initial permeability (µ i ) [22], in maintaining magnetic moments strictly lying in the film plane, as well as the Néel wall for thick films [5], and in achieving improved effects in recording medias [1,[23][24][25]. As an importance parameter, γ is involved in most of the reported works of CoIr films.…”

“…As an importance parameter, γ is involved in most of the reported works of CoIr films. However, few works consider the accurate value of γ, but roughly set it as 17.6 GHz kOe −1 (g = 2) [5,9,22,23,[26][27][28]. To supplement the important γ data for CoIr soft magnetic films, in this study, the γ of oriented hcp Co 1−x Ir x (0.00 ⩽ x ⩽ 0.23) soft magnetic films is investigated according to the electric detection of FMR.…”

Mechanically Cloaked Multiphase Magnetic Elastomer Soft Composites for Wearable Wireless Power Transfer

“…22 For example, liquid metal composites have realized unprecedented thermal and electrical conductivity while maintaining a soft mechanical response, 20,23−31 and high permittivity liquid doping inclusions have been used in elastomers for the creation of flexible triboelectric generators. 32 Magnetic materials provide essential functions to electronics and security such as memory storage, 33,34 sensing, 35,36 actuation, 37 and power transfer. 17,18,38−40 Wearable wireless chargers will allow for seamless charging of portable devices.…”

“…Magnetic materials provide essential functions to electronics and security such as memory storage, , sensing, , actuation, and power transfer. ,,− Wearable wireless chargers will allow for seamless charging of portable devices. As smart devices become more necessary to carry out essential tasks, it is critical for these devices to remain charged and ready for use.…”