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Wetterskog, Erik
Publications (10 of 19) Show all publications
Liao, X., Wang, Y., Wetterskog, E., Cheng, F., Hao, C., Khan, M. T., . . . Yang, S. (2019). Superposition of conventional and spontaneous exchange bias in a Ni50Mn34In13Fe3 magnetic shape memory alloy. Journal of Alloys and Compounds, 772, 988-993
Open this publication in new window or tab >>Superposition of conventional and spontaneous exchange bias in a Ni50Mn34In13Fe3 magnetic shape memory alloy
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2019 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 772, p. 988-993Article in journal (Refereed) Published
Abstract [en]

The conventional exchange bias and spontaneous exchange bias are two interesting but fundamentally different effects in Mn rich Ni-Mn-Z magnetic shape memory alloys. Previous investigations show that these two phenomena appear separately. Here, we report that the conventional and spontaneous exchange bias phenomena coexist in a Ni50Mn34In13Fe3 alloy and the superposition of them increases the total exchange bias of the alloy. Our results suggest that the canonical spin glass and super spin glass may coexist and are embedded in the antiferromagnetic matrix of the martensite, through properly tuning the temperature-field history, which further results in the superposition of conventional and spontaneous exchange bias for this alloy. The interfacial interaction between the canonical spin glass and the antiferromagnetic matrix forms during field cooling process, which results in the conventional exchange bias. Moreover, the application of large magnetic field during the isothermal magnetization process changes the superspin glass into a superferromagnetic state, which interacts with the antiferromagnetic matrix at the interface, causing the spontaneous exchange bias. The superposition of exchange bias provides an effective way to achieve large exchange bias in materials. (C) 2018 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2019
Keywords
Magnetic shape memory alloy, Martensite, Exchange bias, Spin glass
National Category
Condensed Matter Physics Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:uu:diva-369374 (URN)10.1016/j.jallcom.2018.09.068 (DOI)000449651100120 ()
Available from: 2019-01-15 Created: 2019-01-15 Last updated: 2019-01-15Bibliographically approved
Wetterskog, E., Jonasson, C., Smilgies, D.-M., Schaller, V., Johansson, C. & Svedlindh, P. (2018). Colossal Anisotropy of the Dynamic Magnetic Susceptibility in Low-Dimensional Nanocube Assemblies. ACS Nano, 12(2), 1403-1412
Open this publication in new window or tab >>Colossal Anisotropy of the Dynamic Magnetic Susceptibility in Low-Dimensional Nanocube Assemblies
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2018 (English)In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 2, p. 1403-1412Article in journal (Refereed) Published
Abstract [en]

One of the ultimate goals of nanocrystal self-assembly is to transform nanoscale building blocks into a material that displays enhanced properties relative to the sum of its parts. Herein, we demonstrate that 1D needle shaped assemblies composed of Fe3-delta O4 nanocubes display a significant augmentation of the magnetic susceptibility and dissipation as compared to OD and 2D systems. The performance of the nanocube needles is highlighted by a colossal anisotropy factor defined as the ratio of the parallel to the perpendicular magnetization components. We show that the origin of this effect cannot be ascribed to shape anisotropy in its classical sense; as such, it has no analogy in bulk magnetic materials. The temperature-dependent anisotropy factors of the in- and out-of-phase components of the magnetization have an extremely strong particle size dependence and reach values of 80 and 2500, respectively, for the largest nanocubes in this study. Aided by simulations, we ascribe the anisotropy of the magnetic susceptibility, and its strong particle-size dependence to a synergistic coupling between the dipolar interaction field and a net anisotropy field resulting from a partial texture in the 1D nanocube needles.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
Keywords
magnetic properties, ac-susceptibility, anisotropy, magnetic nanoparticles, arrays, supercrystals, assemblies
National Category
Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-351021 (URN)10.1021/acsnano.7b07745 (DOI)000426615600050 ()29328678 (PubMedID)
Funder
NIH (National Institute of Health), DMR-1332208
Available from: 2018-05-18 Created: 2018-05-18 Last updated: 2018-06-05Bibliographically approved
Legaria, E. P., Saldan, I., Svedlindh, P., Wetterskog, E., Gunnarsson, K., Kessler, V. G. & Seisenbaeva, G. A. (2018). Coordination of rare earth element cations on the surface of silica-derived nanoadsorbents. Dalton Transactions, 47(4), 1312-1320
Open this publication in new window or tab >>Coordination of rare earth element cations on the surface of silica-derived nanoadsorbents
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2018 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 4, p. 1312-1320Article in journal (Refereed) Published
Abstract [en]

Silica (SiO2)-derived nanoadsorbents are a powerful and attractive tool for the extraction and separation of rare earth elements (REE) from many perspectives such as reusability, efficiency and minimum impact on the environment. In the present work, we investigated two different methods of adsorption down to the molecular level: (1) the mechanism of the coordination of different groups of REE (light, medium, heavy) with iminodiacetic acid (IDA) was revealed by exploiting models obtained from X-ray crystallography, explaining the selectivity of this type of ligand, and (2) the mechanism of the seeding of RE(OH)(3) initiated by SiO2-based nanoadsorbents was investigated by EXAFS, both individually and in combination with mechanism (1), showing the coexistence of both mechanisms. The REE loaded nanoadsorbents possess a high magnetic susceptibility. This property was studied by magnetometry to quantify the REE adsorption efficiency and compared with the values obtained from complexometry.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Chemical Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-346224 (URN)10.1039/c7dt04388k (DOI)000423465200036 ()29300064 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme, 309373
Available from: 2018-03-15 Created: 2018-03-15 Last updated: 2018-03-28Bibliographically approved
Bender, P., Wetterskog, E., Honecker, D., Fock, J., Frandsen, C., Moerland, C., . . . Johansson, C. (2018). Dipolar-coupled moment correlations in clusters of magnetic nanoparticles. Physical Review B, 98(22), Article ID 224420.
Open this publication in new window or tab >>Dipolar-coupled moment correlations in clusters of magnetic nanoparticles
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2018 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 98, no 22, article id 224420Article in journal (Refereed) Published
Abstract [en]

Here, we resolve the nature of the moment coupling between 10-nm dimercaptosuccinic acid-coated magnetic nanoparticles. The individual iron oxide cores were composed of >95 % maghemite and agglomerated to clusters. At room temperature the ensemble behaved as a superparamagnet according to Mossbauer and magnetization measurements, however, with clear signs of dipolar interactions. Analysis of temperature-dependent ac susceptibility data in the superparamagnetic regime indicates a tendency for dipolar-coupled anticorrelations of the core moments within the clusters. To resolve the directional correlations between the particle moments we performed polarized small-angle neutron scattering and determined the magnetic spin-flip cross section of the powder in low magnetic field at 300 K. We extract the underlying magnetic correlation function of the magnetization vector field by an indirect Fourier transform of the cross section. The correlation function suggests nonstochastic preferential alignment between neighboring moments despite thermal fluctuations, with anticorrelations clearly dominating for next-nearest moments. These tendencies are confirmed by Monte Carlo simulations of such core clusters.

National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-373225 (URN)10.1103/PhysRevB.98.224420 (DOI)000454162800003 ()
Funder
EU, FP7, Seventh Framework Programme, 604448
Available from: 2019-01-14 Created: 2019-01-14 Last updated: 2019-01-14Bibliographically approved
Kumar, A., Wetterskog, E., Lewin, E., Tai, C.-W., Akansel, S., Husain, S., . . . Svedlindh, P. (2018). Effect of in situ electric-field-assisted growth on antiphase boundaries in epitaxial Fe3O4 thin films on MgO. Physical Review Materials, 2(5), Article ID 054407.
Open this publication in new window or tab >>Effect of in situ electric-field-assisted growth on antiphase boundaries in epitaxial Fe3O4 thin films on MgO
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2018 (English)In: Physical Review Materials, ISSN 2475-9953, Vol. 2, no 5, article id 054407Article in journal (Refereed) Published
Abstract [en]

Antiphase boundaries (APBs) normally form as a consequence of the initial growth conditions in all spinel ferrite thin films. These boundaries result from the intrinsic nucleation and growth mechanism, and are observed as regions where the periodicity of the crystalline lattice is disrupted. The presence of APBs in epitaxial films of the inverse spinel Fe3O4 alters their electronic and magnetic properties due to strong antiferromagnetic (AF) interactions across these boundaries. We explore the effect of using in-plane in situ electric-field-assisted growth on the formation of APBs in heteroepitaxial Fe3O4(100)/MgO(100) thin films. The electric-field-assisted growth is found to reduce the AF interactions across APBs and, as a consequence, APB-free thin-film-like properties are obtained, which have been probed by electronic, magnetic, and structural characterization. The electric field plays a critical role in controlling the density of APBs during the nucleation process by providing an electrostatic force acting on adatoms and therefore changing their kinetics. This innovative technique can be employed to grow epitaxial spinel thin films with controlled AF interactions across APBs.

Place, publisher, year, edition, pages
American Physical Society, 2018
Keywords
Fe3O4, Epitaxy, Half-metals, Anti-Phase Boundary, Verwey Transition
National Category
Condensed Matter Physics Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-351161 (URN)10.1103/PhysRevMaterials.2.054407 (DOI)000433037500003 ()
Funder
Knut and Alice Wallenberg Foundation, KAW 2012.0031
Available from: 2018-05-21 Created: 2018-05-21 Last updated: 2018-08-15Bibliographically approved
Tian, B., Liao, X., Svedlindh, P., Strömberg, M. & Wetterskog, E. (2018). Ferromagnetic Resonance Biosensor for Homogeneous and Volumetric Detection of DNA. ACS Sensors, 3(6), 1093-1101
Open this publication in new window or tab >>Ferromagnetic Resonance Biosensor for Homogeneous and Volumetric Detection of DNA
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2018 (English)In: ACS Sensors, ISSN 2379-3694, Vol. 3, no 6, p. 1093-1101Article in journal (Refereed) Published
Abstract [en]

The ability to detect and analyze the state ofmagnetic labels with high sensitivity is of crucial importance fordeveloping magnetic biosensors. In this work, we demonstrate, forthefirst time, a ferromagnetic resonance (FMR) basedhomogeneous and volumetric biosensor for magnetic labeldetection. Two different isothermal amplification methods, i.e.,rolling circle amplification (RCA) and loop-mediated isothermalamplification (LAMP), are adopted and combined with a standardelectron paramagnetic resonance (EPR) spectrometer for FMRbiosensing. For the RCA-based FMR biosensor, binding of RCAproducts of a syntheticVibrio choleraetarget DNA sequence givesrise to the formation of aggregates of magnetic nanoparticles.Immobilization of nanoparticles within the aggregates leads to adecrease of the net anisotropy of the system and a concomitant increase of the resonancefield. A limit of detection of 1 pM isobtained with a linear detection range between 7.8 and 250 pM. For the LAMP-based sensing, a synthetic Zika virus targetoligonucleotide is amplified and detected in 20% serum samples. Immobilization of magnetic nanoparticles is induced by theircoprecipitation with Mg2P2O7(a byproduct of LAMP) and provides a detection sensitivity of 100 aM. The fast measurement,high sensitivity, and miniaturization potential of the proposed FMR biosensing technology makes it a promising candidate fordesigning future point-of-care devices.

National Category
Condensed Matter Physics Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-345595 (URN)10.1021/acssensors.8b00048 (DOI)000436525800005 ()
Funder
Swedish Research Council Formas, 221-2012-444Swedish Research Council Formas, 2011-1692EU, FP7, Seventh Framework Programme, FP7-NMP-601118
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2019-04-24Bibliographically approved
Tian, B., Svedlindh, P., Strömberg, M. & Wetterskog, E. (2018). Ferromagnetic resonance biosensor for homogeneous and volumetric detection of DNA. In: : . Paper presented at Biosensors conference, 12 - 15 June 2018, Miami, United States. , Article ID Abstract No. 0244.
Open this publication in new window or tab >>Ferromagnetic resonance biosensor for homogeneous and volumetric detection of DNA
2018 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Condensed Matter Physics
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-363319 (URN)
Conference
Biosensors conference, 12 - 15 June 2018, Miami, United States
Funder
Swedish Research Council Formas, 221-2012-444Swedish Research Council Formas, 2011-1692EU, FP7, Seventh Framework Programme, FP7-NMP-604448
Available from: 2018-10-16 Created: 2018-10-16 Last updated: 2019-04-24Bibliographically approved
Tian, B., Han, Y., Wetterskog, E., Donolato, M., Fougt Hansen, M., Svedlindh, P. & Strömberg, M. (2018). MicroRNA Detection through DNAzyme-Mediated Disintegration of Magnetic Nanoparticle Assemblies. ACS Sensors, 3, 1884-1891
Open this publication in new window or tab >>MicroRNA Detection through DNAzyme-Mediated Disintegration of Magnetic Nanoparticle Assemblies
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2018 (English)In: ACS Sensors, ISSN 2379-3694, Vol. 3, p. 1884-1891Article in journal (Refereed) Published
Abstract [en]

DNA-assembled nanoparticle superstructures offer numerous bioresponsive properties that can be utilized for point-of-care diagnostics. Functional DNA sequences such as deoxyribozymes (DNAzymes) provide novel bioresponsive strategies and further extend the application of DNA-assembled nanoparticle superstructures. In this work, we describe a microRNA detection biosensor that combines magnetic nanoparticle (MNP) assemblies with DNAzyme-assisted target recycling. The DNA scaffolds of the MNP assemblies contain substrate sequences for DNAzyme and can form cleavage catalytic structures in the presence of target DNA or RNA sequences, leading to rupture of the scaffolds and disintegration of the MNP assemblies. The target sequences are preserved during the cleavage reaction and release into the suspension to trigger the digestion of multiple DNA scaffolds. The high local concentration of substrate sequences in the MNP assemblies reduces the diffusion time for target recycling. The concentration of released MNPs, which is proportional to the concentration of the target, can be quantified by a 405 nm laser-based optomagnetic sensor. For the detection of let-7b in 10% serum, after 1 h of isothermal reaction at 50 degrees C, we found a linear detection range between 10 pM and 100 nM with a limit of detection of 6 pM. For the quantification of DNA target in buffer solution, a limit of detection of 1.5 pM was achieved. Compared to protein enzyme-based microRNA detection methods, the proposed DNAzyme-based biosensor has an increased stability, a reduced cost and a possibility to be used in living cells, all of which are valuable features for biosensing applications.

National Category
Analytical Chemistry Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-363317 (URN)10.1021/acssensors.8b00850 (DOI)000446276300038 ()30188122 (PubMedID)
Funder
Swedish Research Council Formas, 221-2012-444Swedish Research Council Formas, 2011-1692EU, FP7, Seventh Framework Programme, 604448-NanoMag
Available from: 2018-10-16 Created: 2018-10-16 Last updated: 2019-04-24Bibliographically approved
Bender, P., Fock, J., Frandsen, C., Hansen, M. F., Balceris, C., Ludwig, F., . . . Johansson, C. (2018). Relating Magnetic Properties and High Hyperthermia Performance of Iron Oxide Nanoflowers. The Journal of Physical Chemistry C, 122(5), 3068-3077
Open this publication in new window or tab >>Relating Magnetic Properties and High Hyperthermia Performance of Iron Oxide Nanoflowers
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2018 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 5, p. 3068-3077Article in journal (Refereed) Published
Abstract [en]

We investigated, in depth, the interrelations among structure, magnetic properties, relaxation dynamics and magnetic hyperthermia performance of magnetic nanoflowers. The nanoflowers are about 39 nm in size, and consist of densely packed iron oxide cores. They display a remanent magnetization, which we explain by the exchange coupling between the cores, but we observe indications for internal spin disorder. By polarized small-angle neutron scattering, we unambiguously confirm that, on average, the nano flowers are preferentially magnetized along one direction. The extracted discrete relaxation time distribution of the colloidally dispersed particles indicates the presence of three distinct relaxation contributions. We can explain the two slower processes by Brownian and classical Neel relaxation, respectively. The additionally observed very fast relaxation contributions are attributed by us to the relaxation of disordered spins within the nanoflowers. Finally, we show that the intrinsic loss power (ILP, magnetic hyperthermia performance) of the nanoflowers measured in colloidal dispersion at high frequency is comparatively large and independent of the viscosity of the surrounding medium. This concurs with our assumption that the observed relaxation in the high frequency range is primarily a result of internal spin relaxation, and possibly connected to the disordered spins within the individual nanoflowers.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Condensed Matter Physics Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-348119 (URN)10.1021/acs.jpcc.7b11255 (DOI)000424955400067 ()
Funder
EU, FP7, Seventh Framework Programme, 604448
Available from: 2018-04-10 Created: 2018-04-10 Last updated: 2018-04-18Bibliographically approved
Norrbo, I., Curutchet, A., Kuusisto, A., Makela, J., Laukkanen, P., Paturi, P., . . . Lastusaari, M. (2018). Solar UV index and UV dose determination with photochromic hackmanites: from the assessment of the fundamental properties to the device. Materials Horizons, 5(3), 569-576
Open this publication in new window or tab >>Solar UV index and UV dose determination with photochromic hackmanites: from the assessment of the fundamental properties to the device
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2018 (English)In: Materials Horizons, ISSN 2051-6347, E-ISSN 2051-6355, Vol. 5, no 3, p. 569-576Article in journal (Refereed) Published
Abstract [en]

Extended exposure to sunlight or artificial UV sources is a major cause of serious skin and eye diseases such as cancer. There is thus a great need for convenient materials for the easy monitoring of UV doses. While organic photochromic molecules are tunable for responses under different wavelengths of UV radiation, they suffer from rather poor durability because the color changes involve drastic changes in molecular structure. Inorganic materials, on the other hand, are durable, but they have lacked tunability. Here, by combining computational and empirical data, we confirm the mechanism of coloration in the hackmanites, nature-based materials, and introduce a new technique called thermotenebrescence. With knowledge of the mechanism, we show that we can control and thus tune the energy of electronic states of synthetic hackmanites (Na,M)(8)Al6Si6O24(Cl,S)(2) so that their body color is sensitive to the solar UV index as well as UVA, UVB or UVC radiation levels. Finally, we demonstrate that it is possible to use images taken with an inexpensive cell phone to quantify the radiation dose or UV index. The hackmanite materials thus show great potential for use in portable healthcare both in everyday life and in laboratories.

National Category
Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-355466 (URN)10.1039/c8mh00308d (DOI)000431741300026 ()
Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-07-04Bibliographically approved
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