“…We have ruled out that magnetostriction and strain have any effect on this modification of the magnetic anisotropy since we have not observed differences of the Fe 72 Ga 28 lattice parameter with respect to uncoupled single layers. In fact, when strain has been used to manipulate the magnetic anisotropy in Ga-rich FeGa thin films, only the direction within the sample plane was modified 20 . Figure 3 ( a ) In-plane room temperature hysteresis loops recorded for different angles between the reference direction taken as the reference beam direction and the applied magnetic field (filled square) 0°, (filled circle) 30°, and (filled triangle) 60° for the Cr 2 O 3 /Fe 72 Ga 28 (240 nm) sample.…”
Section: Resultsmentioning
confidence: 99%
“…FeGa alloys are extensively studied because of their large magnetostriction constant and low coercivity 13 – 16 . Also interesting is the possibility in sputtered Fe 72 Ga 28 layers of controlling the in-plane magnetic anisotropy by growth conditions 17 – 19 or by thermal treatments combined with mechanical stress 20 . Molecular beam epitaxy (MBE) FeGa can exhibit domain stripes due to a low PMA 21 – 23 , but the general behavior observed by magnetic force microscopy (MFM) in FeGa deposited either by electrodeposition 24 , sputtering 25 or even MBE 26 is a magnetic ripple due to magnetic fluctuations in layers with magnetization in the sample plane.…”
Here it is investigated the effect of the antiferromagnet Cr2O3 on the magnetic properties of ferromagnetic Fe72Ga28 thin films. Sputtered Fe72Ga28 layers have their magnetization in the sample plane with a magnetic fluctuation that gives rise to magnetic ripple. In order to turn its magnetization into the out of plane (OOP) direction, it has been magnetically coupled with Cr2O3 that has magnetic moments along the c-axis, that is the perpendicular direction when properly aligned. Cr2O3 has been obtained from Cr oxidation, whereas Fe72Ga28 has been deposited on top of it by sputtering in the ballistic regime. Although a uniaxial in-plane magnetic anisotropy is expected for Fe72Ga28 thickness above 100 nm, the interfacial coupling with Cr2O3 prevents this anisotropy. The formation of stripe domains in Fe72Ga28 above a critical thickness reveals the enhancement of the out of plane component of the Fe72Ga28 magnetization with respect to uncoupled layers. Due to the interface coupling, the Fe72Ga28 magnetization turns into the out-of-plane direction as its thickness is gradually reduced, and a perpendicular magnetic anisotropy of 3·106 erg·cm−3 is inferred from experimental results. Eventually, the coupling between Cr2O3 and Fe72Ga28 promotes an exchange-bias effect that has been well fitted by means of the random field model.
“…We have ruled out that magnetostriction and strain have any effect on this modification of the magnetic anisotropy since we have not observed differences of the Fe 72 Ga 28 lattice parameter with respect to uncoupled single layers. In fact, when strain has been used to manipulate the magnetic anisotropy in Ga-rich FeGa thin films, only the direction within the sample plane was modified 20 . Figure 3 ( a ) In-plane room temperature hysteresis loops recorded for different angles between the reference direction taken as the reference beam direction and the applied magnetic field (filled square) 0°, (filled circle) 30°, and (filled triangle) 60° for the Cr 2 O 3 /Fe 72 Ga 28 (240 nm) sample.…”
Section: Resultsmentioning
confidence: 99%
“…FeGa alloys are extensively studied because of their large magnetostriction constant and low coercivity 13 – 16 . Also interesting is the possibility in sputtered Fe 72 Ga 28 layers of controlling the in-plane magnetic anisotropy by growth conditions 17 – 19 or by thermal treatments combined with mechanical stress 20 . Molecular beam epitaxy (MBE) FeGa can exhibit domain stripes due to a low PMA 21 – 23 , but the general behavior observed by magnetic force microscopy (MFM) in FeGa deposited either by electrodeposition 24 , sputtering 25 or even MBE 26 is a magnetic ripple due to magnetic fluctuations in layers with magnetization in the sample plane.…”
Here it is investigated the effect of the antiferromagnet Cr2O3 on the magnetic properties of ferromagnetic Fe72Ga28 thin films. Sputtered Fe72Ga28 layers have their magnetization in the sample plane with a magnetic fluctuation that gives rise to magnetic ripple. In order to turn its magnetization into the out of plane (OOP) direction, it has been magnetically coupled with Cr2O3 that has magnetic moments along the c-axis, that is the perpendicular direction when properly aligned. Cr2O3 has been obtained from Cr oxidation, whereas Fe72Ga28 has been deposited on top of it by sputtering in the ballistic regime. Although a uniaxial in-plane magnetic anisotropy is expected for Fe72Ga28 thickness above 100 nm, the interfacial coupling with Cr2O3 prevents this anisotropy. The formation of stripe domains in Fe72Ga28 above a critical thickness reveals the enhancement of the out of plane component of the Fe72Ga28 magnetization with respect to uncoupled layers. Due to the interface coupling, the Fe72Ga28 magnetization turns into the out-of-plane direction as its thickness is gradually reduced, and a perpendicular magnetic anisotropy of 3·106 erg·cm−3 is inferred from experimental results. Eventually, the coupling between Cr2O3 and Fe72Ga28 promotes an exchange-bias effect that has been well fitted by means of the random field model.
“…Finally, to check the quality of the thick Ni 90 Fe 10 layers from the magnetoelastic point of view, we have inferred the value of λ following a routine reported in previous works [33][34][35]. Since the samples studied in this work are polycrystalline, this method can provide an average value for λ.…”
“…Fe 1−x Ga x alloys (0.11 < x < 0.19) usually present an A2 structure [14], or even the D0 3 nanoprecipitation phase can be obtained under slow cooling [15,16]. Ga-rich Fe 1−x Ga x alloys are unusually reported because their phase structures become very complex when the Ga content exceeds x = 0.2 [17][18][19][20]. In addition, it has been reported that the phase structure of the Fe 1−x Ga x alloy is extremely sensitive to heat treatment [13,21,22].…”
In this study, we present a systematic analysis of the relation between the structural properties and magnetic anisotropies of as-grown and heat-treated polycrystalline Fe1−xGax (0.11 < x < 0.19) thin films deposited on glass and Si(100) substrates. The results show that the crystallographic texture of the films has a significant impact on the evolution of the magnetic anisotropies. The samples grown on glass do not exhibit a preferred texture while, for samples grown on Si(100), the appearance of a weak in-plane fourfold magnetic anisotropy is reported. Such anisotropy is enhanced and better defined in the heat treated samples. Via a phenomenological model we show that this anisotropy has a microstructural origin. These findings demonstrate the possibility of tuning magnetic anisotropies by growing on different substrates and/or performing thermal treatments, which in turn reinforces the possibility of developing smart magnetic switching materials for electronic applications.
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