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Publications (10 of 11) Show all publications
Clulow, R., Pramanik, P., Stolpe, A., Joshi, D. C., Mathieu, R., Henry, P. F. & Sahlberg, M. (2024). Phase Stability and Magnetic Properties of Compositionally Complex n=2 Ruddlesden-Popper Perovskites. Inorganic Chemistry, 63(15), 6616-6625
Open this publication in new window or tab >>Phase Stability and Magnetic Properties of Compositionally Complex n=2 Ruddlesden-Popper Perovskites
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2024 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 63, no 15, p. 6616-6625Article in journal (Refereed) Published
Abstract [en]

Four new compositionally complex perovskites with multiple (four or more) cations on the B site of the perovskites have been studied. The materials have the general formula La0.5Sr2.5(M)2O7−δ (M = Ti, Mn, Fe, Co, and Ni) and have been synthesized via conventional solid-state synthesis. The compounds are the first reported examples of compositionally complex n = 2 Ruddlesden–Popper perovskites. The structure and properties of the materials have been determined using powder X-ray diffraction, neutron diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and magnetometry. The materials are isostructural and adopt the archetypal I4/mmm space group with the following unit cell parameters: a ∼ 3.84 Å, and c ∼ 20.1 Å. The measured compositions from energy dispersive X-ray spectroscopy were La0.51(2)Sr2.57(7)Ti0.41(2)Mn0.41(2)Fe0.39(2)Co0.38(1)Ni0.34(1)O7−δ, La0.59(4)Sr2.29(23)Mn0.58(5)Fe0.56(6)Co0.55(6)Ni0.42(4)O7−δ, La0.54(2)Sr2.49(13)Mn0.41(2)Fe0.81(5)Co0.39(3)Ni0.36(3)O7−δ, and La0.53(4)Sr2.55(19)Mn0.67(6)Fe0.64(5)Co0.31(2)Ni0.30(3)O7−δ. No magnetic contribution is observed in the neutron diffraction data, and magnetometry indicates a spin glass transition at low temperatures.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2024
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-528188 (URN)10.1021/acs.inorgchem.3c04277 (DOI)001196512300001 ()38569100 (PubMedID)
Funder
Swedish Foundation for Strategic Research, EM 160039Swedish Research Council, 2019-00207ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 22-92Olle Engkvists stiftelse, 207-0427
Available from: 2024-05-16 Created: 2024-05-16 Last updated: 2024-05-16Bibliographically approved
Pramanik, P., Clulow, R., Joshi, D. C., Stolpe, A., Berastegui, P., Sahlberg, M. & Mathieu, R. (2024). Spin glass states in multicomponent layered perovskites. Scientific Reports, 14(1), Article ID 3382.
Open this publication in new window or tab >>Spin glass states in multicomponent layered perovskites
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2024 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 14, no 1, article id 3382Article in journal (Refereed) Published
Abstract [en]

Temperature-dependent dc-magnetization and ac-susceptibility curves have been recorded for series of single and double layered Ruddlesden-Popper multicomponent perovskites with chemical formula A2BO4 and A3B2O7, respectively, with (La, Sr) on A-sites and up to 7 different cations on the B-sites (Ti, Cr, Mn, Fe, Co, Ni, Cu). The phase purity and chemical homogeneity of the compounds were investigated by X-ray diffraction and energy dispersive X-ray spectroscopy. Independently of the composition, spin glassiness is observed in both systems. Scaling analyses suggest the materials undergo spin glass phase transitions at low temperatures. Yet, qualitative differences are observed between the single-layered and double-layered systems, which are discussed in the light of the spatial dimensionality and magnetic interaction in layered oxide perovskites.

Place, publisher, year, edition, pages
Springer Nature, 2024
National Category
Condensed Matter Physics Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-526186 (URN)10.1038/s41598-024-53896-2 (DOI)001160750400068 ()38336984 (PubMedID)
Funder
Swedish Foundation for Strategic Research, EM 160039Swedish Research Council, 2019-00207Olle Engkvists stiftelse, 207-0427ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 22-92Uppsala University
Available from: 2024-04-08 Created: 2024-04-08 Last updated: 2024-04-16Bibliographically approved
Ghorai, S., Cedervall, J., Clulow, R., Huang, S., Ericsson, T., Häggström, L., . . . Svedlindh, P. (2023). Site-specific atomic substitution in a giant magnetocaloric Fe2P-type system. Physical Review B, 107(10), Article ID 104409.
Open this publication in new window or tab >>Site-specific atomic substitution in a giant magnetocaloric Fe2P-type system
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2023 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 107, no 10, article id 104409Article in journal (Refereed) Published
Abstract [en]

Giant magnetocaloric (GMC) materials constitute a requirement for near room temperature magnetic refrigeration. (Fe,Mn)2(P,Si) is a GMC compound with strong magnetoelastic coupling. The main hindrance towards application of this material is a comparably large temperature hysteresis, which can be reduced by metal site substitution with a nonmagnetic element. However, the (Fe,Mn)2(P,Si) compound has two equally populated metal sites, the tetrahedrally coordinated 3f and the pyramidally coordinated 3g sites. The magnetic and magnetocaloric properties of such compounds are highly sensitive to the site specific occupancy of the magnetic atoms. Here we have attempted to study separately the effect of 3f and 3g site substitution with equal amounts of vanadium. Using formation energy calculations, the site preference of vanadium and its influence on the magnetic phase formation are described. A large difference in the isothermal entropy change (as high as 44\%) with substitution in the 3f and 3g sites is observed. The role of the lattice parameter change with temperature and the strength of the magnetoelastic coupling on the magnetic properties are highlighted.

Place, publisher, year, edition, pages
American Physical Society, 2023
National Category
Condensed Matter Physics Materials Chemistry
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-487262 (URN)10.1103/PhysRevB.107.104409 (DOI)000974419900006 ()
Funder
Swedish Foundation for Strategic Research, EM-16-0039Swedish Research Council, 2019-00645StandUpeSSENCE - An eScience CollaborationSwedish National Infrastructure for Computing (SNIC)
Available from: 2022-10-26 Created: 2022-10-26 Last updated: 2023-05-26Bibliographically approved
Clulow, R. & Lightfoot, P. (2023). Syntheses and crystal structures of three novel oxalate coordination compounds: Rb2Co(C2O4) 2 similar to 4H2O, Rb2CoCl2(C2O4) and K2Li2Cu(C2O4) (3 similar to)2H(2)O. ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, 79, 267-171
Open this publication in new window or tab >>Syntheses and crystal structures of three novel oxalate coordination compounds: Rb2Co(C2O4) 2 similar to 4H2O, Rb2CoCl2(C2O4) and K2Li2Cu(C2O4) (3 similar to)2H(2)O
2023 (English)In: ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, ISSN 2056-9890, Vol. 79, p. 267-171Article in journal (Refereed) Published
Abstract [en]

Single crystals of three novel transition-metal oxalates, dirubidium diaquadioxalatocobalt(II) dihydrate or dirubidium cobalt(II) bis(oxalate) tetrahydrate, Rb-2[Co(C2O4) (2)(H2O)(2)]similar to 2H(2)O, (I), catena-poly[dirubidium [[ dichloridocobalt(II)]-similar to-oxalato]] or dirubidium cobalt(II) dichloride oxalate, {Rb-2[CoCl2(C2O4)]}(n), (II), and poly[dipotassium [tri-similar to-oxalato-copper(II)dilithium] dihydrate] or dipotassium dilithium copper(II) tris(oxalate) dihydrate, {K-2[Li2Cu(C2O4)(3)]similar to 2H(2)O}n, (III), have been grown under hydrothermal conditions and their crystal structures determined using single-crystal X-ray diffraction. The structure of (I) exhibits isolated octahedral [Co(C2O4)(2)(H2O) (2)] units, whereas (II) consists of trans chains of Co2+ ions bridged by bidentate oxalato ligands and (III) displays a novel tri-periodic network of Li+ and Cu2+ ions linked by oxalato bridging ligands.

Place, publisher, year, edition, pages
INT UNION CRYSTALLOGRAPHY, 2023
Keywords
crystal structure, oxalates, coordination, compounds, first-row transition metals.
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-501976 (URN)10.1107/S2056989023001822 (DOI)000968167500005 ()37057014 (PubMedID)
Funder
Swedish Foundation for Strategic Research, EM-16-0039
Available from: 2023-05-22 Created: 2023-05-22 Last updated: 2023-05-22Bibliographically approved
Witman, M. D., Ling, S., Wadge, M., Bouzidi, A., Pineda-Romero, N., Clulow, R., . . . Stavila, V. (2023). Towards Pareto optimal high entropy hydrides via data-driven materials discovery. Journal of Materials Chemistry A, 11(29), 15878-15888
Open this publication in new window or tab >>Towards Pareto optimal high entropy hydrides via data-driven materials discovery
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2023 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 11, no 29, p. 15878-15888Article in journal (Refereed) Published
Abstract [en]

The ability to rapidly screen material performance in the vast space of high entropy alloys is of critical importance to efficiently identify optimal hydride candidates for various use cases. Given the prohibitive complexity of first principles simulations and large-scale sampling required to rigorously predict hydrogen equilibrium in these systems, we turn to compositional machine learning models as the most feasible approach to screen on the order of tens of thousands of candidate equimolar high entropy alloys (HEAs). Critically, we show that machine learning models can predict hydride thermodynamics and capacities with reasonable accuracy (e.g. a mean absolute error in desorption enthalpy prediction of ∼5 kJ molH2−1) and that explainability analyses capture the competing trade-offs that arise from feature interdependence. We can therefore elucidate the multi-dimensional Pareto optimal set of materials, i.e., where two or more competing objective properties can't be simultaneously improved by another material. This provides rapid and efficient down-selection of the highest priority candidates for more time-consuming density functional theory investigations and experimental validation. Various targets were selected from the predicted Pareto front (with saturation capacities approaching two hydrogen per metal and desorption enthalpy less than 60 kJ molH2−1) and were experimentally synthesized, characterized, and tested amongst an international collaboration group to validate the proposed novel hydrides. Additional top-predicted candidates are suggested to the community for future synthesis efforts, and we conclude with an outlook on improving the current approach for the next generation of computational HEA hydride discovery efforts.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2023
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-511740 (URN)10.1039/d3ta02323k (DOI)001023704200001 ()
Funder
NordForsk, 81492
Available from: 2023-09-21 Created: 2023-09-21 Last updated: 2023-09-21Bibliographically approved
Pramanik, A., Manche, A. G., Clulow, R., Lightfoot, P. & Armstrong, A. R. (2022). Exploiting anion and cation redox chemistry in lithium-rich perovskite oxalate: a novel next-generation Li/Na-ion battery electrode. Dalton Transactions, 51(33), 12467-12475
Open this publication in new window or tab >>Exploiting anion and cation redox chemistry in lithium-rich perovskite oxalate: a novel next-generation Li/Na-ion battery electrode
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2022 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 51, no 33, p. 12467-12475Article in journal (Refereed) Published
Abstract [en]

The fundamental understanding of electrochemical reaction kinetics for lithium/sodium-ion batteries (LIBs & NIBs) is a significant criterion for advancing new-generation electrode materials. Herein, we demonstrate a novel lithium-rich perovskite oxalate KLi3Fe(C2O4)(3) (KLFC) cathode with the combination of cation and anion redox delivering discharge capacities of 86 and 99 mA h g(-1) after 100 cycles for a LIB and NIB, respectively, with good cyclability. Experimental Raman spectroscopy analysis combined with DFT calculations of charged/discharged samples illustrate the oxalate anion redox activity. Further, first-principles calculations of the partial density of states and Bader charges analysis have also characterised the redox behaviour and charge transfer during the potassium extraction processes.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2022
National Category
Materials Chemistry Physical Chemistry Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-494472 (URN)10.1039/d2dt01447e (DOI)000831291500001 ()35899863 (PubMedID)
Available from: 2023-01-18 Created: 2023-01-18 Last updated: 2023-01-18Bibliographically approved
Clulow, R., Hedlund, D., Vishina, A., Svedlindh, P. & Sahlberg, M. (2022). Magnetic and Structural Properties of the Fe5Si1-xGexB2 System. Journal of Solid State Chemistry, 316, Article ID 123576.
Open this publication in new window or tab >>Magnetic and Structural Properties of the Fe5Si1-xGexB2 System
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2022 (English)In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 316, article id 123576Article in journal (Refereed) Published
Abstract [en]

A series of compounds with compositions Fe5Si1-xGexB2 were synthesised and their structural and magnetic properties were investigated. The Mo5SiB2-type structure with tetragonal I4/mcm space group is maintained for all compounds with x < 0.15, which is estimated as the compositional limit of the system. The unit cell pa-rameters expand with Ge content before reaching a plateau of a = 5.5581(1) and c = 10.3545(1) angstrom at x = 0.15. The saturation magnetisation (MS) decreased slightly with increasing Ge content whilst the magnetocrystalline anisotropy energy (MAE) remains almost unaffected. The Curie temperature for all compounds studied is at 790 K whilst the spin-reorientation temperature shows suppression from 172 K to 101 K where x = 0.15. Ab Initio calculations reveal an increase in MAE for compositions up to x = 0.25 and a decreased magnitude of MAE of-0.14 MJ/m3 for the hypothetical compound Fe5GeB2 relative to the parent compound Fe5SiB2.

National Category
Condensed Matter Physics
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-473290 (URN)10.1016/j.jssc.2022.123576 (DOI)000863761000008 ()
Funder
Swedish Foundation for Strategic Research, EM-16-0039Swedish Research Council, 2019-00207
Available from: 2022-04-25 Created: 2022-04-25 Last updated: 2022-10-28Bibliographically approved
Rosenqvist Larsen, S., Hedlund, D., Clulow, R., Sahlberg, M., Svedlindh, P., Delczeg-Czirjak, E. K. & Cedervall, J. (2022). Magnetism and magnetic structure determination of a selected (Mn,Co)(23)B-6-compound. Journal of Alloys and Compounds, 905, Article ID 164225.
Open this publication in new window or tab >>Magnetism and magnetic structure determination of a selected (Mn,Co)(23)B-6-compound
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2022 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 905, article id 164225Article in journal (Refereed) Published
Abstract [en]

The vast compositional space in cubic Cr23C6-type compounds (space group Fm3 over line m) opens up possibilities to tune properties by performing substitutions. In this study, the magnetic properties have been explored in a selected (Mn,Co)(23)B-6-compound by the means of synchrotron X-ray diffraction, neutron powder diffraction, magnetometry and electronic structure calculations. Refinements of a structural model based on combined X-ray and neutron diffraction data revealed mixed metal occupancies at all metal positions. However, two sites were richer in Co and the other two showed an abundance of Mn. The magnetic characteristics showed a ferrimagnetic structure below 550 K, with the magnetic moments aligned along the crystallographic c-direction and the magnetic moments on corner atoms having an opposite direction compared to the rest, within the magnetic space group I 4 mm m. The total magnetic moments extracted from magnetometry and neutron diffraction data gave similar values at 6 K, 20.1 and 18.2 mu(B)/f.u., respectively. Results from electronic structure calculations are in reasonable agreement with the experimental findings.& nbsp;(C) 2022 The Author(s). Published by Elsevier B.V. CC_BY_4.0

Place, publisher, year, edition, pages
ElsevierElsevier BV, 2022
Keywords
Magnetism, X-ray diffraction, Neutron diffraction, First principles calculations
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-473658 (URN)10.1016/j.jallcom.2022.164225 (DOI)000779903700003 ()
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research , EM-16-0 039StandUp
Available from: 2022-05-02 Created: 2022-05-02 Last updated: 2024-01-15Bibliographically approved
Borisov, V., Xu, Q., Ntallis, N., Clulow, R., Shtender, V., Cedervall, J., . . . Eriksson, O. (2022). Tuning skyrmions in B20 compounds by 4d and 5d doping. Physical Review Materials, 6(8), Article ID 084401.
Open this publication in new window or tab >>Tuning skyrmions in B20 compounds by 4d and 5d doping
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2022 (English)In: Physical Review Materials, E-ISSN 2475-9953, Vol. 6, no 8, article id 084401Article in journal (Refereed) Published
Abstract [en]

Skyrmion stabilization in novel magnetic systems with the B20 crystal structure is reported here, primarily based on theoretical results. The focus is on the effect of alloying on the 3d sublattice of the B20 structure by substitution of heavier 4d and 5d elements, with the ambition to tune the spin-orbit coupling and its influence on magnetic interactions. State-of-the-art methods based on density functional theory are used to calculate both isotropic and anisotropic exchange interactions. Significant enhancement of the Dzyaloshinskii-Moriya interaction is reported for 5d-doped FeSi and CoSi, accompanied by a large modification of the spin stiffness and spiralization. Micromagnetic simulations coupled to atomistic spin-dynamics and ab initio magnetic interactions reveal the spin-spiral nature of the magnetic ground state and field-induced skyrmions for all these systems. Especially small skyrmions similar to 50 nm are predicted for Co0.75Os0.25Si, compared to similar to 148 nm for Fe0.75Co0.25Si. Convex-hull analysis suggests that all B20 compounds considered here are structurally stable at elevated temperatures and should be possible to synthesize. This prediction is confirmed experimentally by synthesis and structural analysis of the Ru-doped CoSi systems discussed here, both in powder and in single-crystal forms.

Place, publisher, year, edition, pages
American Physical SocietyAmerican Physical Society (APS), 2022
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-482695 (URN)10.1103/PhysRevMaterials.6.084401 (DOI)000838143600001 ()
Funder
Knut and Alice Wallenberg Foundation, 2018.0060Swedish Research Council, 2018-05973Swedish Foundation for Strategic Research, EM-160039Swedish Energy AgencyEU, European Research Council, 854843-FASTCORRStandUpeSSENCE - An eScience CollaborationSwedish Research Council, 201903666Swedish Research Council, 2019-00645Swedish Research Council, 2015-04608Swedish Research Council, 2016-05980Swedish Research Council, 2019-05304
Available from: 2022-08-30 Created: 2022-08-30 Last updated: 2024-01-15Bibliographically approved
Sarkar, T., Ivanov, S., Weil, M., Clulow, R., Lewin, E. & Mathieu, R. (2021). Compositional dependence of the magnetic state of Co3-xZnxTeO6 solid solutions. Journal of Alloys and Compounds, 884, Article ID 161111.
Open this publication in new window or tab >>Compositional dependence of the magnetic state of Co3-xZnxTeO6 solid solutions
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2021 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 884, article id 161111Article in journal (Refereed) Published
Abstract [en]

The magnetic properties of phase-pure solid solutions of Co3-xZnxTeO6 are investigated using magnetometry (single crystals) and neutron diffraction (polycrystalline powders), and compared to results of detailed crystallographic studies. There are five unique Co sites in Co3TeO6, including a tetrahedrally coordinated Co-2 site which Zn preferentially occupies. The magnetic interaction is found to monotonically decrease as the Co-2-O bond length decreases with increasing Zn content. The results suggest a modification of the magnetic structure in the samples containing Zn.

Place, publisher, year, edition, pages
ElsevierElsevier BV, 2021
Keywords
Magnetic oxides, Magnetic dilution, Structure-property correlations, Strongly correlated systems
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-453483 (URN)10.1016/j.jallcom.2021.161111 (DOI)000687466800006 ()
Funder
Swedish Research Council, 2017-05030Swedish Foundation for Strategic Research , EM-16-0039
Note

Title in WoS: Compositional dependence of the magnetic state of Co3-xZnxTeO6 solid solutions

Available from: 2021-09-22 Created: 2021-09-22 Last updated: 2024-01-15Bibliographically approved
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