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Author Cecilia Blanco, M.; De Paoli, J.M.; Ceppi, S.; Tirao, G.; Nassif, V.M.; Guimpel, J.; Carbonio, R.E.
Title Synthesis, structural characterization and magnetic properties of the monoclinic ordered double perovskites BaLaMSbO6, with M = Mn, Co and Ni Type Journal Article
Year 2014 Publication Journal of Alloys and Compounds Abbreviated Journal
Volume 606 Issue Pages 139-148
Keywords Double perovskites; Magnetic properties; X-ray emission spectroscopy; Neutron powder diffraction
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ISSN 0925-8388 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ jguimpel @ Serial 681
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Author Franco, D.G.; Carbonio, R.E.; Nieva, G.
Title Magnetic Properties of the Double Perovskites LaPbMSbO6 (M = Mn, Co, and Ni) Type Journal Article
Year 2013 Publication IEEE Transactions on Magnetics Abbreviated Journal IEEE Trans. Magn.
Volume 49 Issue 8 Pages 4594-4597
Keywords X-ray diffraction; cobalt compounds; lanthanum compounds; lead compounds; magnetisation; manganese compounds; nickel compounds; paramagnetic-antiferromagnetic transitions; space groups; superexchange interactions; LaPbCoSbO6; LaPbMnSbO6; LaPbNiSbO6; M2+ distribution; Rietveld analysis; Sb5+ distribution; X-ray powder diffraction pattern; antiferromagnetic coupling; antiferromagnetic transition; aqueous synthetic route; disorder; double perovskites; ferrimagnetic characteristics; interaction paths; magnetic ions; magnetic properties; monoclinic crystals; octahedral sites; polycrystals; space group P2 1/n; super-superexchange paths; Ions; Magnetic properties; Magnetization; Manganese; Nickel; Temperature measurement; X-ray diffraction; Antiferromagnetic materials; transition metal compounds
Abstract New double perovskites LaPbMSbO6, where M2+ = Mn2+, Co2+, and Ni2+, were synthesized as polycrystals by an aqueous synthetic route at temperatures below 1000 °C. All samples are monoclinic, space group P21/n, as it is observed from Rietveld analysis of X-ray powder diffraction patterns. The distribution of M2+ and Sb5+ among the two octahedral sites have 3% of disorder for M2+ = Ni2+, whereas for M2+ = Mn2+ and Co2+ less disorder is found. The three samples have an antiferromagnetic transition, due to the antiferromagnetic coupling between M2 + through super-superexchange paths M2+-O2--Sb5+-O2--M2+. Transition temperatures are low: 8, 10 and 17 K for Mn2+, Co2+, and Ni2 + respectively, as a consequence of the relatively long distances between the magnetic ions M2+. Besides, for LaPbMnSbO6 a small transition at 45 K was found, with ferrimagnetic characteristics, possibly as a consequence of a small disorder between Mn2+ and Sb5+. This disorder would give additional and shorter interaction paths: superexchange Mn2+-O2--Mn2+.
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Series Volume Series Issue Edition
ISSN 0018-9464 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 669
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Author Franco, D.G.; Carbonio, R.E.; Nieva, G.
Title Synthesis and structural and magnetic characterization of the frustrated magnetic system La2Ni4/3−xCoxSb2/3O6 Type Journal Article
Year 2013 Publication Journal of Solid State Chemistry Abbreviated Journal J. Solid State Chem.
Volume 207 Issue Pages 69-79
Keywords Double perovskites; Neutron diffraction; Rietveld refinement; Ferrimagnetism; Magnetic frustration
Abstract We report the synthesis of double perovskites La2Ni4/3−xCoxSb2/3O6 with x=0, 1/3, 2/3 and 1 by a solid state method. Rietveld refinements of X-ray and neutron powder diffraction data show that all samples crystallize in space group P21/n, with almost perfect occupation of the 2d octahedral site with the transition metals, while all Sb5+ are randomly distributed in a 2c octahedral site. The saturation magnetization in hysteresis loops indicates that the samples are ferrimagnetic throughout all the series. Virgin magnetization curves lie outside hysteresis loops at low temperatures and thermal evolution of Hm – defined as the inflection point of these curves – follows the de Almeida–Thouless dependence for x ≠ 0 . This spin glass like behavior below 30 K is also supported by thermal evolution of the coercivity, which follows an exponential law typical of magnetic clusters, not found in the pure Ni2+ perovskite, x=0 extreme.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 670
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