Thickness and temperature dependence of the dynamic magnetic behavior in disordered FePt films

Mansilla, M. Vásquez; Gómez, J.; Leva, E. Sallica; Gamarra, F. Castillo; Asenjo, A.; Butera, A.

doi:10.1016/j.jmmm.2009.04.045

Cited by 21 publications

(15 citation statements)

References 23 publications

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“…This difference in the resonance field of approximately 900 Oe was not observed in the control composites fabricated in zero field. In the case of uniaxial anisotropy, it is possible to relate 29 the resonance field in the parallel and perpendicular directions with the shape magnetic anisotropy, H r (90 ) À H r (0 ) ¼ (3/2) 2pM s $ 3800 Oe (we have used the reported value for Coferrites, M s ¼ 400 emu/cm 3 ; see Ref. 30).…”

Section: -5mentioning

confidence: 99%

Magnetic and elastic properties of CoFe2O4- polydimethylsiloxane magnetically oriented elastomer nanocomposites

Antonel

Jorge

Pérez

et al. 2011

Journal of Applied Physics

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Magnetic elastic structured composites were prepared by using CoFe 2 O 4 ferromagnetic and superparamagnetic nanoparticles as fillers in polydimethylsiloxane (PDMS) matrixes, which were cured in the presence of a uniform magnetic field. Cobalt-iron oxide nanoparticles of three different average sizes (between 2 and 12 nm) were synthesized and characterized. The smallest nanoparticles presented superparamagnetic behavior, with a blocking temperature of approximately 75 K, while larger particles are already blocked at room temperature. Macroscopically structured-anisotropic PDMS-CoFe 2 O 4 composites were obtained when curing the dispersion of the nanoparticles in the presence of a uniform magnetic field (0.3 T). The formation of the particle's chains (needles) orientated in the direction of the magnetic field was observed only when loading with the larger magnetically blocked nanoparticles. The SEM images show that the needles are formed by groups of nanoparticles which retain their original average size. The Young's moduli of the structured composites are four times larger when measured along the oriented needles than in the perpendicular direction. Magnetization (VSM) and ferromagnetic resonance curves of the structured composites were determined as a function of the relative orientation between the needles and the probe field. The remanence magnetization was 30% higher when measured parallel to the needles, while the coercive field remains isotropic. These observations are discussed in terms of the individual nanoparticle's properties and its aggregation in the composites. V

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Section: -5mentioning

confidence: 99%

Magnetic and elastic properties of CoFe2O4- polydimethylsiloxane magnetically oriented elastomer nanocomposites

Antonel

Jorge

Pérez

et al. 2011

Journal of Applied Physics

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“…12) The magnetoelastic effect or magnetoelastic anisotropy can be described as K me = ¹(3/2)·, where is the magnetostriction constant along the magnetization direction, · is the in-plane stress. 13) Since the FePt alloy has a positive magnetostriction constant, 14,15) in-plane compressive stresses (· < 0) can result in a positive magnetoelastic anisotropy which favours the magnetization in perpendicular direction according to the equation above. However, the PMA of the annealed layered structures cannot be explained solely by the magnetoelastic effect, because the as-deposited films undergo larger compressive stress, nevertheless, they show in-plane magnetic anisotropy.…”

Section: Resultsmentioning

confidence: 99%

Magnetic Behavior of FePt/AlN Layered Structure

et al. 2014

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FePt(x)/AlN(20 nm) layered structures (x = 1.59 nm) were fabricated on fused quartz substrate by magnetron sputtering method. The magnetic behaviors of as-deposited and annealed films have both been studied. It has been found that annealing of the films leads to a transition of magnetic anisotropy from in-plane to perpendicular direction for layered structures with thinner FePt layer thickness. The interface evaluation performed by X-ray reflectivity (XRR) measurement and transmission electron microscopy (TEM) observation indicates that perpendicular magnetic anisotropy of the annealed layered structure can be attributed to the improved interface anisotropy, which is due to the flattening of interfaces. However, for films with thicker FePt layer thickness (above 5 nm), the in-plane anisotropy was enhanced after annealing. The results of stress analysis reveal that the residual stress change inside FePt layers upon annealing can override the interface contribution through magneto-elastic effect in such layer thickness range.

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“…On the other hand, FePt thin films deposited at room temperature tend to grow in a chemically-disordered magnetically-soft fcc phase called A1, with potential applications in magnetoelectronics. The magnetic anisotropy and domain structure of these films have been recently investigated [5][6][7][8][9][10][11][12]. It was found that the domain structure depends on the film thickness and it was suggested that the perpendicular anisotropy that originates the stripe domain pattern could be due to residual stress, crystalline texture, or a combination of both effects.…”

Section: Introductionmentioning

confidence: 99%

Tunable stress induced magnetic domain configuration in FePt thin films

Álvarez¹,

Montalbetti²,

Gómez³

et al. 2015

J. Phys. D: Appl. Phys.

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We present a study of the magnetic properties of chemically disordered ferromagnetic FePt films of 100 nm thickness that have been grown by sputtering with different Ar pressures (3 mTorr ≤ P Ar ≤ 13 mTorr). We found that the residual stress can be controlled by the sputtering pressure, which in turn allows to tune the perpendicular magnetic anisotropy due to magnetoelastic effects.Films deposited at lower Ar pressures display an in-plane compressive stress that favors an out of plane component of the magnetization and the formation of a magnetic domain structure in the form of stripes. For higher pressures the stress is relaxed and the magnetic configuration changes to planar domains. These results show the possibility to accurately tune the initial magnetic state in films with potential applications in magnetoelectrically coupled devices.

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Thickness and temperature dependence of the dynamic magnetic behavior in disordered FePt films

Cited by 21 publications

References 23 publications

Magnetic and elastic properties of CoFe2O4- polydimethylsiloxane magnetically oriented elastomer nanocomposites

Magnetic and elastic properties of CoFe2O4- polydimethylsiloxane magnetically oriented elastomer nanocomposites

Magnetic Behavior of FePt/AlN Layered Structure

Tunable stress induced magnetic domain configuration in FePt thin films

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