Resonance behavior of embedded and freestanding microscale ferromagnets

Abstract

The ferromagnetic resonance of a disordered A2 Fe60Al40 ferromagnetic stripe, of dimensions 5 µm × 1 µm × 32 nm, has been observed in two vastly differing surroundings: in the first case, the ferromagnetic region was surrounded by ordered B2 Fe60Al40, and in the second case it was free standing, adhering only to the oxide substrate. The embedded ferromagnet possesses a periodic magnetic domain structure, which transforms to a single domain structure in the freestanding case. The two cases differ in their dynamic response, for instance, the resonance field for the uniform (k = 0) mode at ~ 14 GHz excitation displays a shift from 209 to 194 mT, respectively for the embedded and freestanding cases, with the external magnetic field applied along the long axis. The resonant behavior of a microscopic ferromagnet can thus be finely tailored via control of its near-interfacial surrounding.

Simulated Guidance in Interpreting Nano-Patterned Co70Fe30 Film Imaging with Differential Phase Contrast

“…In this case, the orientation of the rectangles respective to the external field (i.e., the easy axis of the dipole moment) also plays a role in the resulting domain pattern. Similar studies with good agreement of the magnetic domain structure in ferromagnetic nano-patterns can also be found in other systems [22,23].…”

Transport properties of Fe60Al40 during the B2 to A2 structural phase transition

“…Applications such as magnetic data storage as well as magnetic sensors and spin-transport devices require a precise control of intrinsic magnetic properties at the nano-and meso-scales [1]. An important property is the saturation magnetization, which can be tuned using ion-irradiation induced lattice disordering [2][3][4][5]. Typically, modifications using ion irradiation tends to be a destructive process whereby the penetrating ions suppress lattice ordering, leading to a reduced exchange coupling [3,[6][7][8][9].…”

Resonance-Based Sensing of Magnetic Nanoparticles Using Microfluidic Devices with Ferromagnetic Antidot Nanostructures

“…The method developed by Sushruth can be further improved using a planar microresonator. Microwaves traveling through a planar microresonator ring can be used to excite ferromagnetic resonances in nanoscale ferromagnets; hence, on-chip detectors could be designed with significantly smaller sensing areas [ 36 , 37 ]. Integrating these sensors with microfluidics will further reduce the size of the devices and enable integration of the sensors into lab-on-chip devices [ 38 , 39 , 40 ].…”