| 1. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 2. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 3. |
- Ebersole, Charles R., et al.
(författare)
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Many Labs 5: Testing Pre-Data-Collection Peer Review as an Intervention to Increase Replicability
- 2020
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Ingår i: Advances in Methods and Practices in Psychological Science. - : Sage. - 2515-2467 .- 2515-2459. ; 3:3, s. 309-331
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Tidskriftsartikel (refereegranskat)abstract
- Replication studies in psychological science sometimes fail to reproduce prior findings. If these studies use methods that are unfaithful to the original study or ineffective in eliciting the phenomenon of interest, then a failure to replicate may be a failure of the protocol rather than a challenge to the original finding. Formal pre-data-collection peer review by experts may address shortcomings and increase replicability rates. We selected 10 replication studies from the Reproducibility Project: Psychology (RP:P; Open Science Collaboration, 2015) for which the original authors had expressed concerns about the replication designs before data collection; only one of these studies had yielded a statistically significant effect (p < .05). Commenters suggested that lack of adherence to expert review and low-powered tests were the reasons that most of these RP:P studies failed to replicate the original effects. We revised the replication protocols and received formal peer review prior to conducting new replication studies. We administered the RP:P and revised protocols in multiple laboratories (median number of laboratories per original study = 6.5, range = 3-9; median total sample = 1,279.5, range = 276-3,512) for high-powered tests of each original finding with both protocols. Overall, following the preregistered analysis plan, we found that the revised protocols produced effect sizes similar to those of the RP:P protocols (Delta r = .002 or .014, depending on analytic approach). The median effect size for the revised protocols (r = .05) was similar to that of the RP:P protocols (r = .04) and the original RP:P replications (r = .11), and smaller than that of the original studies (r = .37). Analysis of the cumulative evidence across the original studies and the corresponding three replication attempts provided very precise estimates of the 10 tested effects and indicated that their effect sizes (median r = .07, range = .00-.15) were 78% smaller, on average, than the original effect sizes (median r = .37, range = .19-.50).
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| 4. |
- Arnalds, Unnar B., et al.
(författare)
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Magnetic structure and diffracted magneto-optics of patterned amorphous multilayers
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 82:14, s. 144434-1-144434-8
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Tidskriftsartikel (refereegranskat)abstract
- We present magneto-optical Kerr effect measurements of patterned arrays of Co68Fe24Zr8 / Al2O3 amorphous multilayers. The multilayers were patterned in two dimensions into two different arrangements of circular and ellipsoidal islands. Magnetization loops were recorded in a longitudinal geometry using both the specularly reflected beam as well as diffracted beams scattered off the patterned films. The magnetization of the patterned structures is significantly different from the magnetization of a continuous multilayer owing to the lateral confinement of the pattern and the introduction of additional dipolar coupling between the layers at the edges of the islands. By investigating the magnetic response at the different diffraction orders from the two different configurations of islands we are able to observe the magnetization at different length scales and determine the magnetic response of the circular and ellipsoidal islands individually.
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| 5. |
- Arnalds, Unnar B., et al.
(författare)
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Thermal transitions in nano-patterned XY-magnets
- 2014
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 105:4, s. 042409-
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Tidskriftsartikel (refereegranskat)abstract
- We have fabricated ultra-thin disc shaped islands wherein shape anisotropy confines the moment to the island plane, creating XY-like superspins. At low temperatures, the superspins are blocked, and, as the temperature is increased, they undergo a transition into a superparamagnetic state. The onset of this dynamic superspin state scales with the diameter of the islands, and it persists up to a temperature governed by the intrinsic ordering temperature of the island material defining a range in temperature in which dynamic behavior of the magnetic islands can be obtained.
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| 6. |
- Arnalds, Unnar, et al.
(författare)
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X-ray resonant magnetic scattering from patterned multilayers
- 2012
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 86:6, s. 064426-
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Tidskriftsartikel (refereegranskat)abstract
- We report on x-ray resonant magnetic scattering from laterally patterned arrays of amorphous Co68Fe24Zr8/Al2O3 multilayers. The arrays are composed of circular and ellipsoidal elements which display distinct individual magnetic responses enabling the investigation of the dependence of the observed magnetization on the scattering condition. We focus our attention to special points in reciprocal space, relating to the lateral and perpendicular structure of the samples, thereby revealing the magnetic structure of the multilayered arrays. This allows a comparison of the observed magnetization under different scattering conditions to magneto-optical measurements. The scattering data are supported by micromagnetic simulations which further enhance our understanding of the intricate charge and magnetic scattering from three dimensional patterns.
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| 7. |
- Björck, Matts, 1979-
(författare)
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A Structural Viewpoint of Magnetism in Fe and Co Based Superlattices
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In order to understand the properties of thin film devices, knowledge of the material's structure is essential. The work presented here combines magnetic and structural characterization of the systems studied to gain a deeper physical understanding. The magnetic properties have been studied with a combination of x-ray magnetic circular dichroism, SQUID magnetometry and magneto-optical Kerr effect. For the structural characterization, x-ray reflectivity and diffraction have been used, complemented by neutron diffraction and transmission electron microscopy. One structural property that affects the magnetic moment in metal-on-metal superlattices is interdiffusion between the layers. This is discussed for bcc Fe/Co(001) and bcc Fe81Ni19/Co(001) superlattices. The effect of interdiffusion was seen as a large region of enhanced magnetic moments as compared to theoretical calculations, which assume perfectly sharp interfaces. For the Fe81Ni19/Co(001) superlattices the chemical interface region, as revealed by neutron diffraction, was in good agreement with the region of magnetic enhancement. Another structural property that has been investigated is the strain in the magnetic layers. This does not affect the spin magnetic moment to a large extent. However the magnetocrystalline anisotropy and the orbital moment are affected by the presence of strain. The effects on the orbital moment from strain and interfaces for Fe in Fe/V superlattices was studied, and it was found that the two contributions were separable. In this context the effect of strain on the out-of-plane magnetocrystalline anisotropy in FeCo/Pt has also been studied. The latter system is interesting from a technological perspective since tetragonally distorted FeCo alloys have the potential to be suitable new materials in computer hard drives. Finally, a computer program, based on the Differential Evolution algorithm, to refine primarily x-ray reflectivity data, is presented.
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| 8. |
- Frisk, Andreas, et al.
(författare)
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Strain Engineering for Controlled Growth of Thin-Film FeNi L10
- 2017
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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 50:8
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Tidskriftsartikel (refereegranskat)abstract
- FeNi thin films in the L1(0) phase were successfully grown by magnetron sputtering on HF-etched Si(001) substrates on Cu/Cu100-xNix buffers. The strain of the FeNi layer, (c/a)(FeNi), was varied in a controlled manner by changing the Ni content of the Cu100-xNix buffer layer from x = 0 at.% to x = 90 at.%, which influenced the common in- plane lattice parameter of the CuNi and FeNi layers. The presence of the L1(0) phase was confirmed by resonant x-ray diffraction measurements at various positions in reciprocal space. The uniaxial magnetocrystalline anisotropy energy K-U is observed to be smaller (around 0.35 MJ m(-3)) than predicted for a perfect FeNi L1(0) sample, but it is larger than for previously studied films. No notable variation in K-U with strain state (c/a)(FeNi) is observed in the range achieved (0.99 less than or similar to (c/a)(FeNi) less than or similar to 1.02), which is in agreement with theoretical predictions.
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| 9. |
- George, Jan Peter, et al.
(författare)
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Method comparison of indirect assessments of understory leaf area index (LAIu) : A case study across the extended network of ICOS forest ecosystem sites in Europe
- 2021
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X .- 1872-7034. ; 128
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Tidskriftsartikel (refereegranskat)abstract
- Leaf area index (LAI) is a key ecological indicator for describing the structure of canopies and for modelling energy exchange between atmosphere and biosphere. While LAI of the forest overstory can be accurately assessed over large spatial scales via remote sensing, LAI of the forest understory (LAIu) is still largely ignored in ecological studies and ecosystem modelling due to the fact that it is often too complex to be destructively sampled or approximated by other site parameters. Additionally, so far only few attempts have been made to retrieve understory LAI via remote sensing, because dense canopies with high LAI are often hindering retrieval algorithms to produce meaningful estimates for understory LAI. Consequently, the forest understory still constitutes a poorly investigated research realm impeding ecological studies to properly account for its contribution to the energy absorption capacity of forest stands. This study aims to compare three conceptually different indirect retrieval methodologies for LAIu over a diverse panel of forest understory types distributed across Europe. For this we carried out near-to-surface measurements of understory reflectance spectra as well as digital surface photography over the extended network of Integrated Carbon Observation System (ICOS) forest ecosystem sites. LAIu was assessed by exploiting the empirical relationship between vegetation cover and light absorption (Beer-Lambert- Bouguer law) as well as by utilizing proposed relationships with two prominent vegetation indices: normalized difference vegetation index (NDVI) and simple ratio (SR). Retrievals from the three methods were significantly correlated with each other (r = 0.63–0.99, RMSE = 0.53–0.72), but exhibited also significant bias depending on the LAI scale. The NDVI based retrieval approach most likely overestimates LAI at productive sites when LAIu > 2, while the simple ratio algorithm overestimates LAIu at sites with sparse understory vegetation and presence of litter or bare soil. The purely empirical method based on the Beer-Lambert law of light absorption seems to offer a good compromise, since it provides reasonable LAIu values at both low and higher LAI ranges. Surprisingly, LAIu variation among sites seems to be largely decoupled from differences in climate and light permeability of the overstory, but significantly increased with vegetation diversity (expressed as species richness) and hence proposes new applications of LAIu in ecological modelling.
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| 10. |
- Hase, Thomas P. A., et al.
(författare)
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Proximity effects on dimensionality and magnetic ordering in Pd/Fe/Pd trialyers
- 2014
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 90:10, s. 104403-
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Tidskriftsartikel (refereegranskat)abstract
- The element-specific magnetization and ordering in trilayers consisting of 0.3-1.4 monolayer (ML) thick Fe layers embedded in Pd(001) has been determined using x-ray resonant magnetic scattering. The proximity to Fe induces a large moment in the Pd which extends similar to 2 nm from the interfaces. The magnetization as a function of temperature is found to differ significantly for the Fe and Pd sublattices: The Pd signal resembles the results obtained by magneto-optical techniques with an apparent three-dimensional (3D) to two-dimensional (2D) transition in spatial dimensionality for Fe thickness below similar to 1 ML. In stark contrast, the Fe data exhibits a 2D behavior. No ferromagnetic signal is obtained from Fe below the 2D percolation limit in Fe coverage (similar to 0.7 ML), while Pd shows a ferromagnetic response for all samples. The results are attributed to the temperature dependence of the susceptibility of Pd and a profound local anisotropy of submonolayered Fe.
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