Microwave permeability of ferromagnetic thin films with stripe domain structure

Abstract

We report the observation of multiple permeability peaks for thin ferromagnetic films, in the 10 MHz to 6 GHz range. This behavior is correlated with the presence of perpendicular anisotropy and stripe domains. Because the perpendicular anisotropy is much smaller than the saturation magnetization of the layer, we propose an adaptation of the classical domain mode resonance model to the configuration with oblique magnetization in the stripes.

Magnetodielectric Substrates in Antenna Miniaturization: Potential and Limitations

“…Most of the reported data on demagnetized polycrystalline samples reveal wide-spread resonance curves. However, values of that are as low as 0.2 can be found for both ferromagnetic films [42], [43] and hexagonal ferrites [27] (for all three data the resonant frequency is 1.6 GHz). Generally, if…”

Magnetic Excitations in a Weak-Stripe-Domain Structure: A 2D Dynamic Micromagnetic Approach

“…As a result, microwave permeability spectra exhibiting multiple narrow resonances were reported in amorphous Co-Nb-Zr [6] and Co-Fe-Zr [7] thin films. In the same way, complicated ferromagnetic resonance (FMR) spectra in the unsaturated state with a series of peaks were also observed in Co [8] and FePd [9] thin films.…”

“…On the other hand, the dynamic response of stripe domains to a weak alternating magnetic field dh rf was recently investigated in low or moderate Q-factor magnetic films [6][7][8][9]. As a result, microwave permeability spectra exhibiting multiple narrow resonances were reported in amorphous Co-Nb-Zr [6] and Co-Fe-Zr [7] thin films.…”

Large magneto-elastic anisotropy enhancement with temperature in composition-graded FeCoTa thin films

“…[4][5][6] Among various themes for the research on magnetic anisotropy, the topic of thermal behavior of magnetic anisotropy has been widely investigated and received much attention. [7][8][9] It is commonly known that magnetic anisotropy, especially in the case of magnetocrystalline anisotropy, is decreased with the increasing of temperature.…”