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Ingason, Arni Sigurdur
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Publikasjoner (10 av 22) Visa alla publikasjoner
Novoselova, I. P., Petruhins, A., Wiedwald, U., Ingason, A. S., Hase, T., Magnus, F., . . . Salikhov, R. (2018). Large uniaxial magnetostriction with sign inversion at the first order phase transition in the nanolaminated Mn2GaC MAX phase. Scientific Reports, 8(1), Article ID 2637.
Åpne denne publikasjonen i ny fane eller vindu >>Large uniaxial magnetostriction with sign inversion at the first order phase transition in the nanolaminated Mn2GaC MAX phase
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2018 (engelsk)Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, nr 1, artikkel-id 2637Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

In 2013, a new class of inherently nanolaminated magnetic materials, the so called magnetic MAX phases, was discovered. Following predictive material stability calculations, the hexagonal Mn2GaC compound was synthesized as hetero-epitaxial films containing Mn as the exclusive M-element. Recent theoretical and experimental studies suggested a high magnetic ordering temperature and non-collinear antiferromagnetic (AFM) spin states as a result of competitive ferromagnetic and antiferromagnetic exchange interactions. In order to assess the potential for practical applications of Mn2GaC, we have studied the temperature-dependent magnetization, and the magnetoresistive, magnetostrictive as well as magnetocaloric properties of the compound. The material exhibits two magnetic phase transitions. The Néel temperature is T N  ~ 507 K, at which the system changes from a collinear AFM state to the paramagnetic state. At T t  = 214 K the material undergoes a first order magnetic phase transition from AFM at higher temperature to a non-collinear AFM spin structure. Both states show large uniaxial c-axis magnetostriction of 450 ppm. Remarkably, the magnetostriction changes sign, being compressive (negative) above T t and tensile (positive) below the T t . The sign change of the magnetostriction is accompanied by a sign change in the magnetoresistance indicating a coupling among the spin, lattice and electrical transport properties.

sted, utgiver, år, opplag, sider
London: Nature Publishing Group, 2018
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-145680 (URN)10.1038/s41598-018-20903-2 (DOI)
Tilgjengelig fra: 2018-03-15 Laget: 2018-03-15 Sist oppdatert: 2018-03-15bibliografisk kontrollert
Ingason, A. S., Pålsson, G. K., Dahlqvist, M. & Rosén, J. (2016). Long-range antiferromagnetic order in epitaxial Mn2GaC thin films from neutron reflectometry. PHYSICAL REVIEW B, 94(2), 024416
Åpne denne publikasjonen i ny fane eller vindu >>Long-range antiferromagnetic order in epitaxial Mn2GaC thin films from neutron reflectometry
2016 (engelsk)Inngår i: PHYSICAL REVIEW B, ISSN 2469-9950, Vol. 94, nr 2, s. 024416-Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The nature of the magnetic structure in magnetic so-called MAX phases is a topic of some controversy. Here we present unpolarized neutron-diffraction data between 3.4 and 290.0 K and momentum transfer between Q = 0.0 and 1.1 angstrom(-1), as well as complementary x-ray-diffraction data on epitaxial thin films of the MAX phase material Mn2GaC. This inherently layered material exhibits neutron-diffraction peaks consistent with long-ranged antiferromagnetic order with a periodicity of two structural unit cells. The magnetic structure is present throughout the measured temperature range. The results are in agreement with first-principles calculations of antiferromagnetic structures for this material where the Mn-C-Mn atomic trilayers are found to be ferromagnetically coupled internally but spin flipped or rotated across the Ga layers. The present findings have significant bearing on the discussion regarding the nature of the magnetic structure in magnetic MAX phases.

sted, utgiver, år, opplag, sider
AMER PHYSICAL SOC, 2016
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-130382 (URN)10.1103/PhysRevB.94.024416 (DOI)000379501200005 ()
Merknad

Funding Agencies|European Research Council (ERC) under the European Communitys Seventh Framework Programme FP7 (ERC Grant) [258509]; Swedish Research Council [621-2012-4425]; Knut and Alice Wallenberg Foundation program

Tilgjengelig fra: 2016-08-15 Laget: 2016-08-05 Sist oppdatert: 2017-11-03
Dahlqvist, M., Ingason, A. S., Alling, B., Magnus, F., Thore, A., Petruhins, A., . . . Rosén, J. (2016). Magnetically driven anisotropic structural changes in the atomic laminate Mn2GaC. Physical Review B, 93(1), 014410
Åpne denne publikasjonen i ny fane eller vindu >>Magnetically driven anisotropic structural changes in the atomic laminate Mn2GaC
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2016 (engelsk)Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 93, nr 1, s. 014410-Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Inherently layered magnetic materials, such as magnetic M(n+1)AX(n) (MAX) phases, offer an intriguing perspective for use in spintronics applications and as ideal model systems for fundamental studies of complex magnetic phenomena. The MAX phase composition M(n+1)AX(n) consists of M(n+1)AX(n) blocks separated by atomically thin A-layers where M is a transition metal, A an A-group element, X refers to carbon and/or nitrogen, and n is typically 1, 2, or 3. Here, we show that the recently discovered magnetic Mn2GaC MAX phase displays structural changes linked to the magnetic anisotropy, and a rich magnetic phase diagram which can be manipulated through temperature and magnetic field. Using first-principles calculations and Monte Carlo simulations, an essentially one-dimensional (1D) interlayer plethora of two-dimensioanl (2D) Mn-C-Mn trilayers with robust intralayer ferromagnetic spin coupling was revealed. The complex transitions between them were observed to induce magnetically driven anisotropic structural changes. The magnetic behavior as well as structural changes dependent on the temperature and applied magnetic field are explained by the large number of low energy, i.e., close to degenerate, collinear and noncollinear spin configurations that become accessible to the system with a change in volume. These results indicate that the magnetic state can be directly controlled by an applied pressure or through the introduction of stress and show promise for the use of Mn2GaC MAX phases in future magnetoelectric and magnetocaloric applications.

sted, utgiver, år, opplag, sider
AMER PHYSICAL SOC, 2016
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-124463 (URN)10.1103/PhysRevB.93.014410 (DOI)000367779000005 ()
Merknad

Funding Agencies|European Research Council under the European Communities Seventh Framework Programme (FP7)/ERC Grant [258509]; Swedish Research Council (VR) [642-2013-8020, 621-2011-4417]; KAW Fellowship program; SSF synergy grant FUNCASE; VR Grant [621-2011-4426]; Russian Federation Ministry for Science and Education [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program

Tilgjengelig fra: 2016-02-02 Laget: 2016-02-01 Sist oppdatert: 2017-11-30
Karlsson, L., Birch, J., Mockuté, A., Sigurdur Ingason, A., Ta, H. Q., Rummeli, M. H., . . . Persson, P. O. Å. (2016). Residue reduction and intersurface interaction on single graphene sheets. Carbon, 100, 345-350
Åpne denne publikasjonen i ny fane eller vindu >>Residue reduction and intersurface interaction on single graphene sheets
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2016 (engelsk)Inngår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 100, s. 345-350Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Large regions of pristine graphene are essential to applications which rely on the ideal graphene properties. Common methods for transferring chemical vapour deposition grown graphene to suitable substrates leaves metal oxide particles and poly(methyl methacrylate) (PMMA) residues on opposing surfaces, which degrade the properties. A common method to reduce the residues include annealing in vacuum or in argon, however, residues remain on the graphene sheet. The present investigation reports on the metal oxide particle ripening and PMMA decomposition on a single graphene sheet during in-situ annealing up to 1300 degrees C in a transmission electron microscope. It is shown that the PMMA residues are increasingly reduced at elevated temperatures although the reduction is strongly correlated to the metal oxide particle coverage on the opposing graphene surface. This is shown to occur as a consequence of an electrostatic interaction between the residues and that this prevents the establishment of large clean areas. (C) 2016 Elsevier Ltd. All rights reserved.

sted, utgiver, år, opplag, sider
Pergamon Press, 2016
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-126123 (URN)10.1016/j.carbon.2016.01.007 (DOI)000369961400040 ()
Merknad

Funding Agencies|Swedish Research Council [621-2012-4359, 622-2008-405, 642-2013-8020]; Olle Engkvist foundation; Knut and Alice Wallenbergs Foundation; European Research Council [258509]; IBS Korea [IBS-RO11-D1]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]

Tilgjengelig fra: 2016-03-15 Laget: 2016-03-15 Sist oppdatert: 2017-11-30bibliografisk kontrollert
Meshkian, R., Ingason, A. S., Arnalds, U. B., Magnus, F., Lu, J. & Rosén, J. (2015). A magnetic atomic laminate from thin film synthesis: (Mo0.5Mn0.5)2GaC. APL MATERIALS, 3(7), Article ID 076102.
Åpne denne publikasjonen i ny fane eller vindu >>A magnetic atomic laminate from thin film synthesis: (Mo0.5Mn0.5)2GaC
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2015 (engelsk)Inngår i: APL MATERIALS, ISSN 2166-532X, Vol. 3, nr 7, artikkel-id 076102Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We present synthesis and characterization of a new magnetic atomic laminate: (Mo0.5Mn0.5)(2)GaC. High quality crystalline films were synthesized on MgO(111) substrates at a temperature of similar to 530 degrees C. The films display a magnetic response, evaluated by vibrating sample magnetometry, in a temperature range 3-300 K and in a field up to 5 T. The response ranges from ferromagnetic to paramagnetic with change in temperature, with an acquired 5T-moment and remanent moment at 3 K of 0.66 and 0.35 mu(B) per metal atom (Mo and Mn), respectively. The remanent moment and the coercive field (0.06 T) exceed all values reported to date for the family of magnetic laminates based on so called MAX phases.

sted, utgiver, år, opplag, sider
American Institute of Physics (AIP): Open Access Journals / AIP Publishing LLC, 2015
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-120878 (URN)10.1063/1.4926611 (DOI)000358923500003 ()
Merknad

Funding Agencies|European Research Council under the European Community Seventh Framework Program [258509]; Swedish Research Council (VR) [642-2013-8020, 621-2012-4425]; KAW Fellowship program; SSF synergy grant FUNCASE; Icelandic Research Fund [141518-051]

Tilgjengelig fra: 2015-08-28 Laget: 2015-08-28 Sist oppdatert: 2018-05-24
Schroeder, J., Ingason, A. S., Rosén, J. & Birch, J. (2015). Beware of poor-quality MgO substrates: A study of MgO substrate quality and its effect on thin film quality. Journal of Crystal Growth, 420, 22-31
Åpne denne publikasjonen i ny fane eller vindu >>Beware of poor-quality MgO substrates: A study of MgO substrate quality and its effect on thin film quality
2015 (engelsk)Inngår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 420, s. 22-31Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Magnesium oxide (MgO) substrates are widely used for fundamental research of a large variety of materials. Our motivation is to make the research community aware of poor-quality MgO substrates. We acquired thirty MgO substrates from six different vendors and demonstrate that single-crystal MgO substrates are not always single crystal, but can consist of multiple domains. These multiple-domain MgO substrates can have a significant impact on research results as demonstrated by a one-to-one correlation between the domain structure of MgO substrates and titanium nitride (TiN) thin films (i.e. poor-quality MgO substrates result in poor-quality TiN films). Poor-quality MgO substrates are shown to be a widespread problem with over 70% of the evaluated substrates exhibiting multiple domains, essentially disqualifying them as substrates for epitaxy. MgO substrate vendors and researchers are encouraged to work together to resolve the problem of inconsistent MgO substrate quality and the research community is encouraged to perform quality control of MgO substrates prior to thin film deposition. Quality control by vendors and/or researchers can be achieved by acquiring X-ray diffraction omega-phi maps in batch processes, as detailed in this paper. We also propose a simple quality grading system to differentiate MgO substrates of varying quality.

sted, utgiver, år, opplag, sider
Elsevier, 2015
Emneord
Characterization; Crystal morphology; High resolution X-ray diffraction; Substrates; Solid phase epitaxy; Magnesium oxide
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-118838 (URN)10.1016/j.jcrysgro.2015.03.010 (DOI)000353825100005 ()
Merknad

Funding Agencies|Linkoping University; Swedish Research Council (the RAC Frame Program) [2011-6505]; Linnaeus Grant (LiLi-NFM); European Research Council under the European Community Seventh Framework Program/ERC Grant [258509]; Knut and Alice Wallenberg (KAW) Fellowship program

Tilgjengelig fra: 2015-06-08 Laget: 2015-06-04 Sist oppdatert: 2017-12-04
Salikhov, R., Semisalova, A. S., Petruhins, A., Ingason, A. S., Rosén, J., Wiedwald, U. & Farle, M. (2015). Magnetic Anisotropy in the (Cr0.5Mn0.5)(2)GaC MAX Phase. MATERIALS RESEARCH LETTERS, 3(3), 156-160
Åpne denne publikasjonen i ny fane eller vindu >>Magnetic Anisotropy in the (Cr0.5Mn0.5)(2)GaC MAX Phase
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2015 (engelsk)Inngår i: MATERIALS RESEARCH LETTERS, ISSN 2166-3831, Vol. 3, nr 3, s. 156-160Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Magnetic MAX phase (Cr0.5Mn0.5)(2)GaC thin films grown epitaxially on MgO(111) substrates were studied by ferromagnetic resonance at temperatures between 110 and 300 K. The spectroscopic splitting factor g = 2.00 +/- 0.01 measured at all temperatures indicates pure spin magnetism in the sample. At all temperatures we find the magnetocrystalline anisotropy energy to be negligible which is in agreement with the identified pure spin magnetism.

sted, utgiver, år, opplag, sider
TAYLOR & FRANCIS INC, 2015
Emneord
Magnetic MAX Phase; Ferromagnetic Resonance; g-Factor; Magnetic Anisotropy
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-127070 (URN)10.1080/21663831.2015.1036324 (DOI)000372219300006 ()
Merknad

Funding Agencies|EC [280670]; UDE; ERC [258509]; Swedish Research Council (VR) [642-2013-8020]; SSF synergy grant FUNCASE

Tilgjengelig fra: 2016-04-13 Laget: 2016-04-13 Sist oppdatert: 2018-03-15
Petruhins, A., Ingason, A. S., Lu, J., Magnus, F., Olafsson, S. & Rosén, J. (2015). Synthesis and characterization of magnetic (Cr0.5Mn0.5)2GaC thin films. Journal of Materials Science, 50(13), 4495-4502
Åpne denne publikasjonen i ny fane eller vindu >>Synthesis and characterization of magnetic (Cr0.5Mn0.5)2GaC thin films
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2015 (engelsk)Inngår i: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 50, nr 13, s. 4495-4502Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Growth of (Cr0.5Mn0.5)2GaC thin films from C, Ga, and compound Cr0.5Mn0.5 targets is reported for depositions on MgO (111), 4H-SiC (0001), and Al2O3 (0001) with and without a NbN (111) seed layer. Structural quality is found to be highly dependent on the choice of substrate with MgO (111) giving the best results as confirmed by X-ray diffraction and transmission electron microscopy. Phase pure, high crystal quality MAX phase thin films are realized, with a Cr:Mn ratio of 1:1. Vibrating sample magnetometry shows a ferromagnetic component from 30 K up to 300 K, with a measured net magnetic moment of 0.67 μB per metal (Cr + Mn) atom at 30 K and 5 T. The temperature dependence of the magnetic response suggests competing magnetic interactions with a resulting non-collinear magnetic ordering.

sted, utgiver, år, opplag, sider
Springer Berlin/Heidelberg, 2015
Emneord
magnetism, thin films, magnetron sputtering, MAX phase
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-118837 (URN)10.1007/s10853-015-8999-8 (DOI)000354093500005 ()
Merknad

At the time for thesis presentation publication was in status: Manuscript

Funding Agencies|European Research Council under the European Community [258509]; Swedish Research Council (VR) [642-2013-8020, 621-2012-4425]; KAW Fellowship program; SSF synergy grant FUNCASE; Icelandic University Research fund

Tilgjengelig fra: 2015-06-08 Laget: 2015-06-04 Sist oppdatert: 2018-03-15bibliografisk kontrollert
Meshkian, R., Sigurdur Ingason, A., Dahlqvist, M., Petruhins, A., Arnalds, U. B., Magnus, F., . . . Rosén, J. (2015). Theoretical stability, thin film synthesis and transport properties of the Mon+1GaCn MAX phase. Physica Status Solidi. Rapid Research Letters, 9(3), 197-201
Åpne denne publikasjonen i ny fane eller vindu >>Theoretical stability, thin film synthesis and transport properties of the Mon+1GaCn MAX phase
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2015 (engelsk)Inngår i: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 9, nr 3, s. 197-201Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The phase stability of Mon +1GaCn has been investigated using ab-initio calculations. The results indicate stability for the Mo2GaC phase only, with a formation enthalpy of 0.4 meV per atom. Subsequent thin film synthesis of Mo2GaC was performed through magnetron sputtering from elemental targets onto Al2O3 [0001], 6H-SiC [0001] and MgO [111] substrates within the temperature range of 500 degrees C and 750 degrees C. High structural quality films were obtained for synthesis on MgO [111] substrates at 590 degrees C. Evaluation of transport properties showed a superconducting behavior with a critical temperature of approximately 7 K, reducing upon the application of an external magnetic field. The results point towards the first superconducting MAX phase in thin film form.

sted, utgiver, år, opplag, sider
Wiley-VCH Verlag, 2015
Emneord
superconducting MAX phases; Mo2GaC; ab-initio calculations; magnetron sputtering; thin films
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-117388 (URN)10.1002/pssr.201409543 (DOI)000351674600009 ()
Merknad

Funding Agencies|European Research Council under European Community/ERC [258509]; Swedish Research Council (VR) [642-2013-8020, 621-2012-4425]; KAW Fellowship program; SSF synergy grant FUNCASE; Icelandic Research Fund

Tilgjengelig fra: 2015-04-24 Laget: 2015-04-24 Sist oppdatert: 2018-05-24
Ingason, A. S., Mockute, A., Dahlqvist, M., Magnus, F., Olafsson, S., Arnalds, U., . . . Rosén, J. (2014). A Nanolaminated Magnetic Phase: Mn2GaC. Materials Research Letters, 2(2), 89-93
Åpne denne publikasjonen i ny fane eller vindu >>A Nanolaminated Magnetic Phase: Mn2GaC
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2014 (engelsk)Inngår i: Materials Research Letters, ISSN 2166-3831, Vol. 2, nr 2, s. 89-93Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Layered magnetic materials are fascinating from the point of view of fundamental science as well as applications. Discoveries such as giant magnetoresistance (GMR) in magnetic multilayers have revolutionized data storage and magnetic recording, and concurrently initiated the search for new layered magnetic materials. One group of inherently nanolaminated compounds are the so called Mn+1AXn (MAX) phases. Due to the large number of isostructural compositions, researchers are exploring the wide range of interesting properties, and not primarily functionalization through optimization of structural quality. Magnetic MAX phases have been discussed in the literature, though this is hitherto an unreported phenomenon. However, such materials would be highly interesting, based on the attractive and useful properties attained with layered magnetic materials to date. Here we present a new MAX phase, (Cr1–xMnx)2GeC, synthesized as thin film in heteroepitaxial form, showing single crystal material with unprecedented structural MAX phase quality. The material was identified using first-principles calculations to study stability of hypothetical MAX phases, in an eort to identify a potentially magnetic material. The theory predicts a variety of magnetic behavior depending on the Mn concentration and Cr/Mn atomic conguration within the sublattice. The analyzed thin films display a magnetic signal well above room temperature and with partly ferromagnetic ordering. These very promising results open up a field of new layered magnetic materials, with high potential for electronics and spintronics applications.

sted, utgiver, år, opplag, sider
Taylor & Francis, 2014
Emneord
MAX phases, sputtering, transmission electron microscopy (TEM), ab initio calculation
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-77774 (URN)10.1080/21663831.2013.865105 (DOI)
Merknad

On the day of the defence date the status of this article was previous Manuscript. The original title of the Manuscript was Magnetic nanoscale laminates from first principles and thin film synthesis.

Tilgjengelig fra: 2012-05-29 Laget: 2012-05-29 Sist oppdatert: 2018-03-15bibliografisk kontrollert
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