306 research outputs found
Voltage-induced strain control of the magnetic anisotropy in a Ni thin film on flexible substrate
Voltage-induced magnetic anisotropy has been quantitatively studied in
polycrystalline Ni thin film deposited on flexible substrate using microstrip
ferromagnetic resonance. This anisotropy is induced by a piezoelectric actuator
on which the film/substrate system was glued. In our work, the control of the
anisotropy through the applied elastic strains is facilitated by the compliant
elastic behavior of the substrate. The in-plane strains in the film induced by
the piezoelectric actuation have been measured by the digital image correlation
technique. Non-linear variation of the resonance field as function of the
applied voltage is found and well reproduced by taking into account the non
linear and hysteretic variations of the induced in-plane strains as function of
the applied voltage. Moreover, we show that initial uniaxial anisotropy
attributed to compliant substrate curvature is fully compensated by the voltage
induced anisotropy.Comment: 7 pages, 6 figures, published in the Journal of Applied Physic
Micro-strip ferromagnetic resonance study of strain-induced anisotropy in amorphous FeCuNbSiB film on flexible substrate
The magnetic anisotropy of a FeCuNbSiB (Finemet) film deposited on Kapton has
been studied by micro-strip ferromagnetic resonance technique. We have shown
that the flexibility of the substrate allows a good transmission of elastic
strains generated by a piezoelectric actuator. Following the resonance field
angular dependence, we also demonstrate the possibility of controlling the
magnetic anisotropy of the film by applying relatively small voltages to the
actuator. Moreover, a suitable model taking into account the effective elastic
strains measured by digital image correlation and the effective elastic
coefficients measured by Brillouin light scattering, allowed to deduce the
magnetostrictive coefficient. This latter was found to be positive
) and consistent with the usually reported values for
bulk amorphous FeCuNbSiB.Comment: 9 pages, 8 figure
Structural, static and dynamic magnetic properties of CoMnGe thin films on a sapphire a-plane substrate
Magnetic properties of CoMnGe thin films of different thicknesses (13, 34,
55, 83, 100 and 200 nm), grown by RF sputtering at 400{\deg}C on single crystal
sapphire substrates, were studied using vibrating sample magnetometry (VSM) and
conventional or micro-strip line (MS) ferromagnetic resonance (FMR). Their
behavior is described assuming a magnetic energy density showing twofold and
fourfold in-plane anisotropies with some misalignment between their principal
directions. For all the samples, the easy axis of the fourfold anisotropy is
parallel to the c-axis of the substrate while the direction of the twofold
anisotropy easy axis varies from sample to sample and seems to be strongly
influenced by the growth conditions. Its direction is most probably monitored
by the slight unavoidable angle of miscut the Al2O3 substrate. The twofold
in-plane anisotropy field is almost temperature independent, in contrast with
the fourfold field which is a decreasing function of the temperature. Finally,
we study the frequency dependence of the observed line-width of the resonant
mode and we conclude to a typical Gilbert damping constant of 0.0065 for the
55-nm-thick film.Comment: 7 pages, 7 figures, To be published (Journal of Applied Physics
Bending strain-tunable magnetic anisotropy in Co2FeAl Heusler thin film on Kapton
Bending effect on the magnetic anisotropy in 20 nm CoFeAl Heusler thin
film grown on Kapton\textregistered{} has been studied by ferromagnetic
resonance and glued on curved sample carrier with various radii. The results
reported in this letter show that the magnetic anisotropy is drastically
changed in this system by bending the thin films. This effect is attributed to
the interfacial strain transmission from the substrate to the film and to the
magnetoelastic behavior of the CoFeAl film. Moreover two approaches to
determine the in-plane magnetostriction coefficient of the film, leading to a
value that is close to , have been proposed.Comment: 4 pages, 4 figure
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