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Publications (10 of 35) Show all publications
Riordan, E., Blomgren, J., Jonasson, C., Ahrentorp, F., Johansson, C., Margineda, D., . . . Giblin, S. R. (2019). Design and implementation of a low temperature, inductance based high frequency alternating current susceptometer.. Paper presented at 2019/08/08. Review of Scientific Instruments, 90(7)
Open this publication in new window or tab >>Design and implementation of a low temperature, inductance based high frequency alternating current susceptometer.
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2019 (English)In: Review of Scientific Instruments, Vol. 90, no 7Article in journal (Refereed) Published
Abstract [en]

We report on the implementation of an induction based, low temperature, high frequency ac susceptometer capable of measuring at frequencies up to 3.5 MHz and at temperatures between 2 K and 300 K. Careful balancing of the detection coils and calibration allow a sample magnetic moment resolution of 5 × 10−10 Am2 at 1 MHz. We discuss the design and characterization of the susceptometer and explain the calibration process. We also include some example measurements on the spin ice material CdEr2S4 and iron oxide based nanoparticles to illustrate functionality.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39702 (URN)10.1063/1.5074154 (DOI)
Conference
2019/08/08
Available from: 2019-08-08 Created: 2019-08-08 Last updated: 2019-08-08Bibliographically approved
Jonasson, C., Schaller, V., Zeng, L., Olsson, E., Frandsen, C., Castro, A., . . . Johansson, C. (2019). Modelling the effect of different core sizes and magnetic interactions inside magnetic nanoparticles on hyperthermia performance. Journal of Magnetism and Magnetic Materials, 477, 198-202
Open this publication in new window or tab >>Modelling the effect of different core sizes and magnetic interactions inside magnetic nanoparticles on hyperthermia performance
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2019 (English)In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 477, p. 198-202Article in journal (Refereed) Published
Abstract [en]

We present experimental intrinsic loss power (ILP) values, measured at an excitation frequency of 1 MHz and at relatively low field amplitudes of 3.4 to 9.9 kA/m, as a function of the mean core diameter, for selected magnetic nanoparticle (MNP). The mean core sizes ranged from ca. 8 nm to 31 nm. Transmission electron microscopy indicated that those with smaller core sizes (less than ca. 22 nm) were single-core MNPs, while those with larger core sizes (ca. 29 nm to 31 nm) were multi-core MNPs. The ILP data showed a peak at ca. 20 nm. We show here that this behaviour correlates well with the predicted ILP values obtained using either a non-interacting Debye model, or via dynamic Monte-Carlo simulations, the latter including core-core magnetic interactions for the multi-core particles. This alignment of the models is a consequence of the low field amplitudes used. We also present interesting results showing that the core-core interactions affect the ILP value differently depending on the mean core size.

Keywords
magnetic nanoparticles, magnetic interactions, magnetic relaxation, Monte-Carlo simulations, multi-core particles, single-core particles
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36361 (URN)10.1016/j.jmmm.2018.09.117 (DOI)2-s2.0-85060279115 (Scopus ID)
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2019-06-27Bibliographically approved
Sriviriyakul, T., Bogren, S., Schaller, V., Jonasson, C., Blomgren, J., Ahrentorp, F., . . . Johansson, C. (2019). Nanorheological studies of xanthan/water solutions using magnetic nanoparticles. Journal of Magnetism and Magnetic Materials, 473, 268-271
Open this publication in new window or tab >>Nanorheological studies of xanthan/water solutions using magnetic nanoparticles
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2019 (English)In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 473, p. 268-271Article in journal (Refereed) Published
Abstract [en]

We show results of nanorheological studies of different concentrations of xanthan (non-Newtonian fluid) in water using magnetic nanoparticles (MNPs) together with the AC susceptibility (ACS) vs frequency method. For comparison we also show the ACS response for different concentrations of glycerol in water (Newtonian fluid). The ACS response is measured, and the data is modelled using dynamic magnetic models and different viscoelastic models. We study the ACS response (in-phase and out-of-phase ACS components) at different concentrations of xanthan in water (up to 1 wt% xanthan) and with a constant concentration of MNPs. We use MNP systems that show Brownian relaxation (sensitive to changes in the environmental properties around the MNPs). ACS measurements are performed using the DynoMag system. The Brownian relaxation of the MNP system peak is shifting down in frequency and the ACS response is broadening and decreases due to changes in the viscoelastic properties around the MNPs in the xanthan solution. The viscosity and the storage moduli are determined at each excitation frequency and compared with traditional macroscopic small amplitude oscillatory shear rheological measurements. The results from the traditional rheological and nanorheological measurements correlate well at higher xanthan concentration.

Place, publisher, year, edition, pages
Elsevier B.V., 2019
Keywords
AC susceptibility, Brownian relaxation, Glycerol, Magnetic multi-core nanoparticles, Nanorheological measurements, Xanthan, Brownian movement, Digital storage, Magnetic susceptibility, Nanoparticles, Non Newtonian flow, Non Newtonian liquids, Rheology, Viscoelasticity, Ac susceptibility (ACS), Brownian relaxations, Magnetic nano-particles, Magnetic nanoparti cles (MNPs), Multi core, Viscoelastic properties, Nanomagnetics
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35560 (URN)10.1016/j.jmmm.2018.09.103 (DOI)2-s2.0-85055085870 (Scopus ID)
Note

; Funding details: Svenska Forskningsrådet Formas; Funding details: 2016-00253, Svenska Forskningsrådet Formas; Funding text: The authors acknowledge Josefine Mosser for assistance with experimental work. This project receives funding from The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning ( FORMAS ) under grant number 2016-00253 .

Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2019-06-27Bibliographically approved
Elmquist, L., Carlsson, R. & Johansson, C. (2018). Cast iron components with intelligence. In: : . Paper presented at Mater. Sci. Forum. 4 September 2017 through 7 September 2017 (pp. 512-519). , 925
Open this publication in new window or tab >>Cast iron components with intelligence
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

The paper describes a project with the aim to develop communicating and functional cast iron components in smart systems. The concept is based on sensors integrated into cast iron components; this will influence not only the component but also the casting process. Among the technical challenges is how to choose a sensor solution that cost-efficiently and with minimal environmental impact can be integrated into the component during the casting process, and especially without being damaged during mold filling and the high pouring temperature. Another challenge is how the iron will interact and interfere with sensor signals and whether an insulating intermediate material is needed or not. Integrating the sensors into the casting makes sensors a natural part of the component, which in turn can lead to more resource efficient designs, increased value added for the casting sector, and a general access to different possibilities of digitalization. The integrated sensors can be used for effective control and monitoring of components when in service and give information about for example how the component is used and what conditions it is exposed to. In other words, the component can tell when maintenance is needed or in worst cases, indicate that something is wrong before a failure will happen. Important measurands can e.g. be elongation, shear, temperature and vibration. Different combinations of sensor materials and insulating materials and their interaction with the cast iron have been investigated. It is shown how the interaction at the interface affects the microstructure and consequently the properties of the cast iron. In the case of insulating materials it is e.g. shown how air gaps are formed and in the case of sensor materials it is shown how a diffusion zone is formed and how this zone depends on the sensor material. How this diffusion zone affects the microstructure is discussed.

Keywords
Cast iron, Digitalized castings, Integrated sensors, Intelligent cast components, Intelligent castings, Interfacial phenomena, Environmental impact, Insulating materials, Insulation, Microstructure, Molds, Cast components, Control and monitoring, Intermediate materials, Pouring temperatures, Technical challenges, Without being damaged
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34469 (URN)10.4028/www.scientific.net/MSF.925.512 (DOI)2-s2.0-85050011551 (Scopus ID)9783035710557 (ISBN)
Conference
Mater. Sci. Forum. 4 September 2017 through 7 September 2017
Note

Funding details: VINNOVA;

Available from: 2018-08-09 Created: 2018-08-09 Last updated: 2019-06-27Bibliographically 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) Submitted
Abstract [en]

nanocubes display a significant augmentation of the magnetic susceptibility and dissipation as compared to 0D 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.

Keywords
ac-susceptibility, anisotropy, arrays, assemblies, magnetic nanoparticles, magnetic properties, supercrystals
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33343 (URN)10.1021/acsnano.7b07745 (DOI)29328678 (PubMedID)2-s2.0-85042705323 (Scopus ID)
Available from: 2018-02-28 Created: 2018-02-28 Last updated: 2019-06-27Bibliographically approved
Carlsson, R., Elmquist, L., Thore, A., Ahrentorp, F., Johansson, C. & Israelsson, B. (2018). Connecting sensors inside smart castings. In: : . Paper presented at 7 th International Symposium on Aircraft Materials (ACMA2018) April 24-26, 2018, Compiègne (France).
Open this publication in new window or tab >>Connecting sensors inside smart castings
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2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

The paper presents ongoing research on smart metal castings, meaning the technologicalinnovation of elevating cast metal components into metal components with integratedsensor functionality. Since the innovation targets aim straight at low cost industrial serialproduction, specific high cost and high-end solutions like inclusion of advancedelectronic equipment and after mounted sensors are not part of this innovationdevelopment. Integrating signal carriers inside metal castings to achieve metal castingswith sensor functionality requires robust solutions for connecting the sensor signal to thesensor interrogator and interpreter. The actual transmission of the signal may be donewirelessly or by wire. However, for several reasons there is a challenge with establishingan isolated and distinct connection between the sensor contact, and the contact at theexternal connection, regardless of whether it is to an antenna for wireless transmission orto a wire. This paper presents metallurgical challenges associated with choices ofmaterials, and combinations of metallurgical challenges and production process relatedchallenges, including the high melting temperatures. Aims are to find the rightcombinations of metal alloys, production simplicity, signal stability and robustness. Thepaper will present some of the tests made in the project so far. The project is run in aconsortium of the two Sweden-based industrial companies Husqvarna and SKF, and thetwo Swedish research institutes Swerea SWECAST and RISE Acreo.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34921 (URN)
Conference
7 th International Symposium on Aircraft Materials (ACMA2018) April 24-26, 2018, Compiègne (France)
Available from: 2018-08-23 Created: 2018-08-23 Last updated: 2019-06-27Bibliographically approved
Blomgren, J., Ahrentorp, F., Ilver, D., Jonasson, C., Sepehri, S., Kalaboukhov, A., . . . Johansson, C. (2018). Development of a sensitive induction-based magnetic nanoparticle biodetection method. Nanomaterials, 8(11), Article ID 887.
Open this publication in new window or tab >>Development of a sensitive induction-based magnetic nanoparticle biodetection method
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2018 (English)In: Nanomaterials, ISSN 2079-4991, Vol. 8, no 11, article id 887Article in journal (Refereed) Published
Abstract [en]

We developed a novel biodetection method for influenza virus based on AC magnetic susceptibility measurement techniques (the DynoMag induction technique) together with functionalized multi-core magnetic nanoparticles. The sample consisting of an incubated mixture of magnetic nanoparticles and rolling circle amplified DNA coils is injected into a tube by a peristaltic pump. The sample is moved as a plug to the two well-balanced detection coils and the dynamic magnetic moment in each position is read over a range of excitation frequencies. The time for making a complete frequency sweep over the relaxation peak is about 5 minutes (10 Hz–10 kHz with 20 data points). The obtained standard deviation of the magnetic signal at the relaxation frequency (around 100 Hz) is equal to about 10−5 (volume susceptibility SI units), which is in the same range obtained with the DynoMag system. The limit of detection with this method is found to be in the range of 1 pM. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords
AC susceptibility, Brownian relaxation, Magnetic biosensing, Magnetic nanoparticles, Multi-core particles
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36359 (URN)10.3390/nano8110887 (DOI)2-s2.0-85056217345 (Scopus ID)
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2019-06-27Bibliographically approved
Gao, S., Zaharko, O., Tsurkan, V., Prodan, L., Riordan, E., Lago, J., . . . Fennell, T. (2018). Dipolar Spin Ice States with a Fast Monopole Hopping Rate in CdEr2X4 (X = Se, S). Physical Review Letters, 120(13), Article ID 130201.
Open this publication in new window or tab >>Dipolar Spin Ice States with a Fast Monopole Hopping Rate in CdEr2X4 (X = Se, S)
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2018 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 120, no 13, article id 130201Article in journal (Refereed) Published
Abstract [en]

Excitations in a spin ice behave as magnetic monopoles, and their population and mobility control the dynamics of a spin ice at low temperature. CdEr2Se4 is reported to have the Pauling entropy characteristic of a spin ice, but its dynamics are three orders of magnitude faster than the canonical spin ice Dy2Ti2O7. In this Letter we use diffuse neutron scattering to show that both CdEr2Se4 and CdEr2S4 support a dipolar spin ice state-the host phase for a Coulomb gas of emergent magnetic monopoles. These Coulomb gases have similar parameters to those in Dy2Ti2O7, i.e., dilute and uncorrelated, and so cannot provide three orders faster dynamics through a larger monopole population alone. We investigate the monopole dynamics using ac susceptometry and neutron spin echo spectroscopy, and verify the crystal electric field Hamiltonian of the Er3+ ions using inelastic neutron scattering. A quantitative calculation of the monopole hopping rate using our Coulomb gas and crystal electric field parameters shows that the fast dynamics in CdEr2X4 (X = Se, S) are primarily due to much faster monopole hopping. Our work suggests that CdEr2X4 offer the possibility to study alternative spin ice ground states and dynamics, with equilibration possible at much lower temperatures than the rare earth pyrochlore examples.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33635 (URN)10.1103/PhysRevLett.120.137201 (DOI)2-s2.0-85044749863 (Scopus ID)
Note

Foundation under Grants No. 20021-140862, No. 20020- 162626, and the SCOPES project No. IZ73Z0-152734/1.

Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2019-06-27Bibliographically 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 Mössbauer 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
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-37023 (URN)10.1103/PhysRevB.98.224420 (DOI)2-s2.0-85058959420 (Scopus ID)
Note

 Funding details: Danmarks Frie Forskningsfond, DFF; Funding details: 604448;

Available from: 2019-01-17 Created: 2019-01-17 Last updated: 2019-06-27Bibliographically approved
Bender, P., Fock, J., Hansen, M. F., Bogart, L. K., Southern, P., Ludwig, F., . . . Johansson, C. (2018). Influence of clustering on the magnetic properties and hyperthermia performance of iron oxide nanoparticles. Nanotechnology, 29(42), Article ID 425705.
Open this publication in new window or tab >>Influence of clustering on the magnetic properties and hyperthermia performance of iron oxide nanoparticles
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2018 (English)In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 29, no 42, article id 425705Article in journal (Refereed) Published
Abstract [en]

Clustering of magnetic nanoparticles can drastically change their collective magnetic properties, which in turn may influence their performance in technological or biomedical applications. Here, we investigate a commercial colloidal dispersion (FeraSpin™R), which contains dense clusters of iron oxide cores (mean size around 9 nm according to neutron diffraction) with varying cluster size (about 18-56 nm according to small angle x-ray diffraction), and its individual size fractions (FeraSpin™XS, S, M, L, XL, XXL). The magnetic properties of the colloids were characterized by isothermal magnetization, as well as frequency-dependent optomagnetic and AC susceptibility measurements. From these measurements we derive the underlying moment and relaxation frequency distributions, respectively. Analysis of the distributions shows that the clustering of the initially superparamagnetic cores leads to remanent magnetic moments within the large clusters. At frequencies below 105 rad s-1, the relaxation of the clusters is dominated by Brownian (rotation) relaxation. At higher frequencies, where Brownian relaxation is inhibited due to viscous friction, the clusters still show an appreciable magnetic relaxation due to internal moment relaxation within the clusters. As a result of the internal moment relaxation, the colloids with the large clusters (FS-L, XL, XXL) excel in magnetic hyperthermia experiments.

Keywords
core-clusters, magnetic hyperthermia, magnetic nanoparticles, multi-core particles, nanoflowers, numerical inversion, Colloids, Iron oxides, Magnetic moments, Magnetic susceptibility, Medical applications, Nanoparticles, Neutron diffraction, Magnetic nano-particles, Multi core, Nanomagnetics
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35651 (URN)10.1088/1361-6528/aad67d (DOI)2-s2.0-85052695672 (Scopus ID)
Note

This project (NanoMag) has received funding from the European Commission Framework Programme 7 under grant agreement no 604448.

Available from: 2018-11-08 Created: 2018-11-08 Last updated: 2019-06-27Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6662-8023

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