Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
Refine search result
1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Ivanov, Sergey A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Ritter, C.
    Tellgren, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Golubko, N
    Mosunov, A
    Politova, E D
    Weil, M
    Chemical pressure effects on structural, dielectric and magnetic properties of solid solutions Mn3-xCoxTeO62014In: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 50, p. 42-56Article in journal (Refereed)
    Abstract [en]

    The effects of Co2+ doping on the structural, magnetic and dielectric properties of the multiferroic frustrated antiferromagnet Mn3TeO6 have been investigated. Ceramic samples of the solid solution series Mn3-xCoxTeO6 were prepared by a solid-state reaction route. X-ray and neutron powder diffraction and electron microscopy techniques were combined with calorimetric, dielectric and magnetic measurements to investigate the dependence of the crystal structure and physical properties on temperature and composition. It is shown that the compounds with x <= 2.4 adopt the trigonal corundum-related structure of pure Mn3TeO6 (space group 18) in the temperature range 5-295 K and that the lattice parameters a and c and the unit-cell volume V decrease linearly with increasing Co2+ concentration. The low-temperature magnetic susceptibility and heat capacity data evidence the antiferromagnetic ordering of all samples. The Neel temperature linearly increases with Co2+ concentration x. Curie-Weiss fits of the high temperature susceptibility indicate that the magnetic frustration decreases with x. The derived magnetic structure of Mn3TeO6 can be described as an incommensurately modulated magnetic spin state with k = [0, 0, k(z)] and an elliptical spin-spiral order of spins within the chains of MnO6 octahedra. With increasing Co2+ concentration the propagation vector kz changes from 0.453 (x = 0) to 0.516 (x = 2.4). The magnetic anisotropy changes as well, leading to a reorientation of the spiral-basal plane. A possible coexistence of long-range order of electrical dipoles and magnetic moments in Mn3-xCoxTeO6 is discussed.

  • 2.
    Ivanov, Sergey A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Tellgren, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Ritter, C
    Instittue Laue Langevin, Grenoble, Frankrike.
    Golubko, N V
    Dept of Inorganic Materials, Karpov' Institute of Physical Chemistry, Moskva, Ryssland.
    Politova, E D
    Dept of Inorganic Materials, Karpov' Institute of Physical Chemistry, Moskva, Ryssland.
    Weil, M
    Institute for Chemical Tecnologies and Analytics, Vienna University of Technology, Vienna, Österrike.
    New type of incommensurate magnetic ordering in Mn(3)TeO(6)2011In: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 46, no 11, p. 1870-1877Article in journal (Refereed)
    Abstract [en]

    The complex metal oxide Mn(3)TeO(6) exhibits a corundum related structure and has been prepared both in forms of single crystals by chemical transport reactions and of polycrystalline powders by a solid state reaction route. The crystal structure and magnetic properties have been investigated using a combination of X-ray and neutron powder diffraction, electron microscopy, calorimetric and magnetic measurements. At room temperature this compound adopts a trigonal structure, space group R (3) over bar with a = 8.8679(1) angstrom. c = 10.6727(2) angstrom. A long-range magnetically ordered state is identified below 23 K. An unexpected feature of this magnetic structure is several types of Mn-chains. Under the action of the incommensurate magnetic propagation vector k = [0, 0, 0.4302(1)] the unique Mn site is split into two magnetically different orbits. One orbit forms a perfect helix with the spiral axis along the c-axis while the other orbit has a sine wave character along the c-axis.

  • 3.
    Ivanov, Sergey A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Tellgren, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Porcher, F.
    Ericsson, Tore
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Mosunov, A.
    Beran, P.
    Korchaginaa, S.K.
    Anil Kumar, Puri
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Preparation, structural, dielectric and magnetic properties of LaFeO3-PbTiO3 solid solutions2012In: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 47, no 11, p. 3253-3268Article in journal (Refereed)
    Abstract [en]

    Solid solutions of (1−x)LaFeO3–(x)PbTiO3 (0 < x < 1) have been prepared by conventional solid-state reaction. These complex perovskites have been studied by means of X-ray (XRPD) and neutron powder (NPD) diffraction, complemented with dielectric, magnetic, heat capacity and Mössbauer measurements. Complete solubility in the perovskite series was demonstrated. The NPD and XRPD patterns were successfully refined as orthorhombic (x ≤ 0.7) and tetragonal (x ≥ 0.8). A composition-driven phase transformation occurs within the interval 0.7 < x < 0.8. The samples with x < 0.5 showed evidence of long-range magnetic ordering with an G-type antiferromagnetic arrangement of the magnetic moments of the Fe3+ cations in the B-site with propagation vector k = (0,0,0). Based on the obtained experimental data, a combined structural and magnetic phase diagram has been constructed. The factors governing the structural, dielectric and magnetic properties of (1−x)LaFeO3–(x)PbTiO3 solid solutions are discussed, as well as their possible multiferroicity.

  • 4.
    Ivanov, Sergey A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Tellgren, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ritter, C.
    Institute Laue Langevin, Grenoble, Frankrike.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Andre, G.
    Laboratoire Leon Brillouin, CEA, Saclay, Frankrike.
    Golubko, N. V.
    Dept of Inorganic Materials, Karpov' Institute of Physical Chemistry, Moskva, Ryssland.
    Politova, E. D.
    Dept of Inorganic Materials, Karpov' Institute of Physical Chemistry, Moskva, Ryssland.
    Weil, M.
    Institute for Chemical Technologies and Analytics, Vienna University of Technology, Wien, Österrike.
    Temperature-dependent multi-k magnetic structure in multiferroic Co3TeO62012In: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 47, no 1, p. 63-72Article in journal (Refereed)
    Abstract [en]

    A complex magnetic order of the multiferroic compound Co(3)TeO(6) has been revealed by neutron powder diffraction studies on ceramics and crushed single crystals. The compound adopts a monoclinic structure (s.g. C2/c) in the studied temperature range 2-300 K but exhibits successive antiferromagnetic transitions at low temperature. Incommensurate antiferromagnetic order with the propagation vector k(1) = (0, 0.485, 0.055) sets in at 26 K. A transition to a second antiferromagnetic structure with k(2) = (0, 0, 0) takes place at 21.1 K. Moreover, a transition to a commensurate antiferromagnetic structure with k(3) = (0, 0.5, 0.25) occurs at 17.4 K. The magnetic structures have been determined by neutron powder diffraction using group theory analysis as a preliminary tool. Different coordinations of the Co(2+) ions involved in the low-symmetry C2/c structure of Co(3)TeO(6) render the exchange-interaction network very complex by itself. The observed magnetic phase transformations are interpreted as an evidence of competing magnetic interactions. The temperature dependent changes in the magnetic structure, derived from refinements of high-resolution neutron data, are discussed and possible mechanisms connected with the spin reorientations are described.

  • 5.
    Ivanov, Sergey
    et al.
    Department of Inorganic Materials, Karpov’ Institute of Physical Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Eriksson, S-G
    Department of Inorganic Chemistry, University of Gothenburg.
    Tellgren, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Rundlöf, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    The magnetoelectric perovskite Sr3Fe2TeO9: An insight from magnetic measurements and neutron powder diffraction2007In: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 42, no 4, p. 776-789Article in journal (Refereed)
    Abstract [en]

    A study of the crystallographic and magnetic structures of the double perovskite Sr3Fe2TeO9 has been carried out on a polycrystalline sample using neutron powder diffraction (NPD) data between 10 and 650 K. An analysis of the NPD patterns at room temperature has shown that this compound crystallises in the tetragonal space group I4/m with a = 5.5614(7) Å and c = 7.867(1) Å and has a partially ordered arrangement of Fe and Te at the B-sites. The compound undergoes an I4/m → Fm-3m improper ferroelectric phase transition near 460 K. A low-temperature ferrimagnetic ordering (below TN = 260 K) has been followed from the magnetisation measurements and sequential NPD data analysis. In good agreement with magnetic measurements the ferrimagnetic structure with very weak magnetisation is defined by the propagation vector k = (0, 0, 0). In addition to the obtained experimental results on magnetic and electric properties some aspects of magnetoelectricity in this perovskite are also discussed and compared with those of another quaternary oxide Sr3Fe2B6+O9.

  • 6.
    Ivanov, Sergey
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Tellgren, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Hewat, A
    Temperature evolution of structure and magnetic properties in the perovskite Sr2MnSbO62009In: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 44, no 4, p. 822-830Article in journal (Refereed)
    Abstract [en]

    The structural and magnetic properties of the perovskite Sr2MnSbO6 have been studied. Combining neutron and X-ray powder diffraction data, the temperature evolution of the structural parameters was investigated with the Rietveld method between 2 and 1000 K. The crystal structure is tetragonal (space group I4/m) within the temperature interval of 2–750 K and cubic (space group Fm-3m) above 750 K. Both octahedral B-site positions were found to be partially occupied by Mn and Sb, but with different Mn/Sb ratios. The magnetic susceptibilities showed irreversibility between field cooled and zero-field cooled (ZFC) conditions and spin glass like magnetic dynamics including aging and memory phenomena at temperatures below 30 K; all appearing well above a broad maximum at 13 K in the ZFC susceptibility curves. This suggests that the material reaches an unconventional spin-glass state at low temperatures, possibly arising from a competitive situation between the double exchange (ferromagnetism) and the super-exchange (antiferromagnetism). Neutron diffraction patterns showed no evidence of a long-range magnetic ordering at 2 K which is consistent with spin glass behavior. The factors governing the observed structural and magnetic properties of Sr2MnSbO6 are discussed and compared with those of other quaternary Mn- and Sb-containing perovskites. Graphs of the temperature of magnetic phase transitions as functions of the cation size were constructed and are discussed for the AB3+1/2B5+1/2O3 series with isomorphous substitution of B3+ and B5+ cations. Possible influence of the A-cation sublattice on magnetic properties is also shortly considered.

  • 7.
    Ivanov, Sergey
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Tellgren, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Rundlöf, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    André, G
    Bourée, F
    Neutron powder diffraction and magnetic study of perovskites Pb(Mn1/2Nb1/2)O3 and Pb(Mn1/4Fe1/4Nb1/2)O32008In: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 43, no 11, p. 3074-3087Article in journal (Refereed)
    Abstract [en]

    The structural and magnetic properties of the complex metal oxides Pb(Mn1/2Nb1/2)O3 (PMNO) and Pb(Mn1/4Fe1/4Nb1/2)O3 (PMFNO), which belong to a class of disordered perovskites have been studied. The magnetic susceptibilities of PMNO showed hysteresis between field cooled and zero-field cooled conditions below the transition of 15 K, suggesting that the material has a spin-glass feature. Neutron diffraction patterns of PMNO showed no evidence of a long-range magnetic ordering at 1.5 K, which is consistent with spin-glass behavior. Rietveld refinements of neutron powder diffraction data collected at different temperatures between 1.5 and 700 K have been carried out in order to extract structural information. The crystal structure of this compound is cubic (space group Pmm) within the whole temperature interval. The Mn and Nb ions were found to be disordered over the perovskite B-sites. The main feature of this structure is the positional disorder at the Pb site, the importance of which in connection with the ferroic transitions is briefly discussed. The Pb cations show a positional disorder shifting from their high-symmetry positions along the [1 1 1] direction. The effect of Fe-doping on PMNO has been studied. The substitution of Fe at the Mn site in PMFNO results in a small changes of the magnetic properties without significant differences in the crystal structures. The factors governing the observed structural and magnetic properties of PMNO and PMFNO are discussed and compared with those of other quaternary Mn-containing perovskites. For the PbB3+1/2Nb1/2O3 series with the isomorphous substitution B3+, graphs of average lattice parameters of the perovskite phase and the temperatures of ferroelectric and magnetic phase transitions as functions of the B3+ cation radius were constructed and are discussed. Influence of A-cation sublattice on magnetic properties is also considered.

  • 8.
    Shtender, Vitalii
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Univ Paris Est, ICMPE UMR7182, CNRS, UPEC, F-94320 Thiais, France.;NAS Ukraine, Karpenko Phys Mech Inst, 5 Naukova St, UA-79060 Lvov, Ukraine..
    Paul-Boncour, Valerie
    Univ Paris Est, ICMPE UMR7182, CNRS, UPEC, F-94320 Thiais, France..
    Denys, Roman
    HYSTORSYS AS, Box 45, NO-2027 Kjeller, Norway..
    Hedlund, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Zavaliy, Ihor
    NAS Ukraine, Karpenko Phys Mech Inst, 5 Naukova St, UA-79060 Lvov, Ukraine..
    Impact of the R and Mg on the structural, hydrogenation and magnetic properties of R3-xMgxCo9 (R = Pr, Nd, Tb and Y) compounds2022In: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 156, article id 111981Article in journal (Refereed)
    Abstract [en]

    R2MgCo9 (R = Pr, Nd, Tb and Y) compounds have been synthesized by a powder sintering method and the corresponding hydrides have been prepared by a solid gas method. Their crystal structures and magnetic properties have been systematically studied. X-ray diffraction analysis showed that all R2MgCo9 compounds belong to the PuNi3-type structure. The elements Tb, Y, Nd, Pr yield a lowering of the equilibrium pressure which correlates well with the increase in cell volume. The R2MgCo9H(D)x (R = Pr, Nd, Tb and Y; (9.4 <= x <= 12)) hydrides (deuterides) preserve the PuNi3-type structure with hydrogenation-induced volume expansion ranging from 14.7 to 19.6%. The substitution of deuterium for hydrogen in R2MgCo9-(H,D)(2) (R = Tb and Y) prevents fast desorption at room temperature and ambient pressure. As for the magnetic properties, all the studied interme-tallic compounds show ferromagnetic or ferrimagnetic behavior, and in some cases a temperature dependent spin reorientation. Hydrogen insertion reduces the magnetization and decreases the magnetic ordering temperature (TC), whereas Mg for R substitution increases TC.

    Download full text (pdf)
    fulltext
1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf