Information on in- and out-of-plane correlated roughness in multilayers from x-ray specular reflectivity

Romanov, V. P.; Ul’yanov, S. V.; Uzdin, V. M.; Nowak, G.; Vadalá, M.; Zabel, H.

doi:10.1088/0022-3727/41/11/115401

Cited by 7 publications

(7 citation statements)

References 22 publications

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“…27 A fit with the Parratt formalism 28 gave a root mean square ͑RMS͒ interface roughness parameter of = 0.2 nm, comparable to earlier reports on similar ͓Fe/ V͔ n superlattice structures. 25,[29][30][31][32][33][34] In Fig. 2 we display Bragg scans of the same three samples in the angular range of the MgO ͑002͒ Bragg peak, where the main Bragg reflections of the epitaxial layers are expected.…”

Section: A Structural Propertiesmentioning

confidence: 99%

Superconducting spin valves based on epitaxial Fe/V superlattices

et al. 2008

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In superconducting spin valves of the type S/F1/N/F2 or F1/S/F2 with a superconducting layer S, two ferromagnetic layers F1 and F2, and a normal metallic layer N, the superconducting transition temperature T S depends on the relative magnetization direction of the ferromagnetic layers F1 and F2. The difference of the transition temperature ⌬T S = T s AP − T s P with the magnetization direction of F1 and F2 either antiparallel or parallel is called the superconducting spin valve effect. We have prepared both types of spin valves by growing Fe/V thin-film heterostructures with epitaxial quality on MgO͑001͒ substrates. In the S/F1/N/F2-type spin valves the ferromagnetic layers were the first two Fe layers of a ͓Fe/V͔ superlattice coupled antiferromagnetically via the interlayer exchange interaction. Here we observed a superconducting spin valve shift of up to ⌬T S Ϸ 200 mK when aligning the sublattice magnetization in an external magnetic field. In the F1/S/F2-type spin valves the ferromagnetic layer F1 was either a ͓Fe/V͔ or a ͓Fe x V 1−x / V͔ superlattice, the F2 layer was a Fe-, a Co-, or a Fe x V 1−x film. Using weakly ferromagnetic Fe x V 1−x alloy layers as F1 and F2 we find a spin valve effect of up to ⌬T S Ϸ 20 mK, which is more than a factor of 2 larger than reported in the literature before for spin valves with comparable transition temperatures. Our results indicate that a high interface transparency and a large superconducting correlation length are prerequisites for the observation of a sizable superconducting spin valve effect.

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Section: A Structural Propertiesmentioning

confidence: 99%

Superconducting spin valves based on epitaxial Fe/V superlattices

et al. 2008

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“…26 XRR accesses the layer thicknesses, the interface roughness, and the correlation function parallel and perpendicular to the layers. 27,28 Additionally, XRD provides data on the crystalline structure of the individual layers, their epitaxial relationship, and their strain state. Furthermore, transverse scans in the epitaxial plane and perpendicular to it yield information on the mosaic spreads and grain size.…”

Section: Structural Characterizationmentioning

confidence: 99%

Magnetization and magnetization reversal in epitaxial Fe/Cr/Co asymmetric spin-valve systems

et al. 2012

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We have investigated asymmetric Fe/Cr/Co/Cr superlattices with two magnetic layers of Fe and Co, which are different with respect to their magnetic properties: magnetization, coercivity, and magnetic anisotropy. The magnetic layers are weakly coupled via a mediating Cr spacer layer providing an antiferromagnetic alignment of adjacent layers. The magnetic structure of these spin-valve-like Fe/Cr/Co/Cr superlattices was analyzed from the remanent state up to saturation via polarized neutron scattering and polarized neutron reflectivity (PNR). Furthermore, the domain structure in remanence was imaged via polarized x-ray photoemission electron microscopy (XPEEM). This analysis reveals that the Co magnetization strongly affects the Fe domain structure, while the layer magnetization is collinear from the remanent antiparallel state up to the ferromagnetic saturation state. However, for certain Co layer thicknesses, the as-grown remanent state exhibits a noncollinear antiferromagnetic spin structure, which cannot be recovered after applying a magnetic field. However, the noncollinear structure is reproducible with freshly grown superlattices.

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“…For multilayers containing N layers located in ͑x ; y͒ plane, Eq. ͑1͒ can be written in the form [14][15][16][17]…”

Section: ͑1͒mentioning

confidence: 99%

“…Most of the experimental spectra show a slower decay at large angles. [15][16][17][20][21][22] This means that the contribution of diffuse scattering to the specular spectra have to be taken into account for a proper interpretation of the data.…”

Section: Analysis Of the Experimental Datamentioning

confidence: 99%

Separation of the diffuse contribution to the specular x-ray scattering of multilayer films

et al. 2010

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X-ray reflectivity measurements from multilayer films contain information not only about the layer thickness and interface roughness but also about correlations of the interface roughness parallel and perpendicular to the interface. Due to the finite size of the receiving detector slit, it collects both purely specular and diffusely scattered radiation. Separation of the diffuse contribution to the spectra of specular reflectivity is an important task of processing the experimental data. For this purpose we suggest and implement a measurement method for specularly scattered scans integrated over several solid angles determined by the size of detector slits. Since in all cases the specular reflectivities coincide, this approach allows a separation of the diffuse and pure specular contributions. This separation is, in turn, required for obtaining information about the in-and out-of-plane structural correlation lengths. The method was used to analyze the experimental data of two multilayer systems with different interface properties: MgO/ ͓V͑1.212 nm͒ / Fe͑0.715 nm͔͒ 25 / V͑24.24 nm͒ / Pd͑5-8 nm͒ and SiO 2 / Si/ ͓CoFeB͑2.55 nm͒ / MgO͑1.8 nm͔͒ 15 .

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Information on in- and out-of-plane correlated roughness in multilayers from x-ray specular reflectivity

Cited by 7 publications

References 22 publications

Superconducting spin valves based on epitaxial Fe/V superlattices

Superconducting spin valves based on epitaxial Fe/V superlattices

Magnetization and magnetization reversal in epitaxial Fe/Cr/Co asymmetric spin-valve systems

Separation of the diffuse contribution to the specular x-ray scattering of multilayer films

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