Increasing Operational Frequency in Microwave Devices by Using [SmCo/NiFe] Multilayered Structures

Long-range magnetic interactions and proximity effects in an amorphous exchange-spring magnet

“…Finally, the two distinctly different regions of observed magnetic coupling, with different temperature dependence and extent, hint at the existence of a rich magnetic phase diagram for amorphous materials and an extensive scope for tailoring of their properties. This tuneability through temperature or composition can, for example, allow the increase of operating frequencies in microwave devices 31 , increase the performance of exchange-spring layer recording media 32 33 or even add new functionality in areas such as magnetic sensors or logic, where a controllable interlayer coupling is desired. As a result, amorphous magnetic films may have an important role to play in future spintronic devices.…”

High-frequency signal processing using magnetic layered structures

“…Our theoretical calculations [38] have shown that a multilayer made up of repeated units of Fe/SmCo could be used in notch filters and band-pass filters, which would operate in the 50-100 GHz range. Initial experimental data on a [NiFe/ SmCo] 15 multilayer show an upshift of about 10-15 GHz in the operational frequency compared to the Permalloy alone [39]. (3) The introduction of an effective anisotropy in the magnetic material.…”

Tunable resonant properties of perpendicular anisotropy [Co/Pd]/Fe/[Co/Pd] multilayers

“…Exchange-spring structures, the coupling of hard (or, more generally, high anisotropy) materials and soft materials, are being pursued for applications such as permanent magnet, 1,2 magnetic recording, magnetic memories, and high frequency materials to name a few. [4][5][6][7][8][9][10][11][12][13] By coupling the soft to the hard layer, it possible to tune both the static and dynamic responses of the soft layer and derive new functionality. Such coupling can be applied to enhance properties in perpendicular magnetic recording media, 3,4 as well as tuning the reversal properties in high-density bit patterned media [5][6][7][8][9][10] and can be further optimized for microwave assisted magnetic recording.…”

“…11 The exchange coupling of the soft layer to the hard layer is also being pursued as a pathway for raising the resonant frequency of the soft layer 12 and the operating frequencies of planar microwave devices. 13 When the soft layer is either pinned or exchange-coupled at the interface of the hard layer, there are significant shifts in the resonance frequency, with only a small reduction in the strength of the resonance. Such coupled structures are also being pursued in spin-torque devices.…”