Positive magnetoresistance effect in rare earth cobaltites

Troyanchuk, I. O.; Бушинский, М. В.; Karpinsky, D. V.; Dobryanskii, V. M.; Sikolenko, V.; Балагуров, А. М.

doi:10.1134/s0021364009070029

Cited by 7 publications

(8 citation statements)

References 16 publications

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“…In addition, the antiferromagnet-ferromagnet transition has clearly pronounced cooperative features [4], which are incompatible with the behavior of the system of clus ters. However, in contrast to magnetic semiconductors and manganites [7], cobaltites exhibit neither signifi cant anomalies in the electrical conductivity nor a pronounced magnetoresistive effect near the Curie point [8,9]. It is important to note the absence of a complete set of solid solutions between the LaCoO 3 and LaBaCo 2 O 5.5 phases [10].…”

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First-order magnetic phase transition in layered Sr3YCo4O10.5 + δ-type cobaltites

et al. 2012

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Complex cobalt oxides with perovskite structure attract significant current interest owing to the possi bility of different spin states in the Co 3+ ion and their closely related magnetic and transport characteristics [1]. For example, in layered LnBaCo 2 O 5.5 (Ln = lan thanide) cobaltites, metal-insulator and antiferro magnet-"ferromagnet" transitions were observed. The latter transition is accompanied by anomalies in transport properties and by the giant magnetoresistive effect [2,3]. The magnetoresistive effect manifests itself in single crystals along only one crystallographic axis [4] and has little in common with the isotropic colossal magnetoresistance in magnetic semiconduc tors and manganites. In this class of compounds, the ferromagnetic component is not due to the existence of ferromagnetic clusters in the antiferromagnetic host material since it produces a coherent magnetic contri bution to neutron scattering [5,6]. In addition, the antiferromagnet-ferromagnet transition has clearly pronounced cooperative features [4], which are incompatible with the behavior of the system of clus ters. However, in contrast to magnetic semiconductors and manganites [7], cobaltites exhibit neither signifi cant anomalies in the electrical conductivity nor a pronounced magnetoresistive effect near the Curie point [8,9]. It is important to note the absence of a complete set of solid solutions between the LaCoO 3 and LaBaCo 2 O 5.5 phases [10]. Therefore, it is reason able to state that the compound with the nominal composition Gd 0.9 Ba 0.1 CoO 3 described in [11] is actu ally a mixture of the GdCoO 3 and GdBaCo 2 O 5.5 phases. Another class of anion deficient layered cobaltites was produced quite recently. It has the chemical composition Sr 3 LnCo 4 O 10.5 + δ (its reduced chemical formula is Sr 0.75 Ln 0.25 CoO 3 -γ ), where the rare earth ions can partially substitute for strontium ions and vice versa [12][13][14][15]. Its crystal structure is built by alternating anion deficient CoO 4 + δ layers and lay ers formed by CoO 6 octahedra with sharing vertices. This class of compounds is characterized by high mag netic ordering temperature (up to 360 K) [16][17][18]. Spontaneous magnetization appears below 360 K, attains its maximum value near room temperature, and then decreases gradually down to liquid helium temperatures [16][17][18][19][20]. Several conjectures explaining the anomalous temperature dependence of the mag netization have been put forward. In [21], it was sug gested that a certain fraction of Co 3+ ions undergo the transition from the high spin to low spin state with a decrease in temperature. However, the neutron dif fraction studies do not reveal any anomalous decrease in the magnetic moment when the temperature is decreased [19,20,22]. In the whole temperature range below the magnetic ordering point, the antiferromag netic G type structure was observed, whereas it was impossible to reliably detect the ferromagnetic contri bution since it turned out to be quite small. For this reason, in [19,20], the ano...

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“…The polycrystalline ceramic samples under study, Sr 3.2 Y 0 8. Co 4 O 10.5 + δ , Sr 3 YCo 4 O 10.5 + δ , and Sr 2.6 Y 1.4 Co 4 O 10.5 + δ (their reduced chemical formula is Sr 1 -x Y x CoO 3 -γ , where x = 0.2, 0.25, and 0.35, respectively), were produced using the conventional ceramic technology.…”

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First-order magnetic phase transition in layered Sr3YCo4O10.5 + δ-type cobaltites

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“…Perovskite rare-earth cobaltites (RE)CoO3 have attracted considerable research interest recently due to their intriguing magnetic properties [1][2][3]. Additionally, useful material properties such as temperature-induced metal-insulator transitions and thermoelectricity have been reported as well [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Synthesis, Microstructure, and Magnetic Properties of Rare-Earth Cobaltites

et al. 2016

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Citation for published item:quti¡ errez eij sD tuli nd r doEqonj lD tes¡ us nd ¡ evil fr ndeD h vid nd erryD s n nd wor¡ nD imilio nd hmidtD iner @PHIUA 9wi row veE ssisted synthesisD mi rostru tureD nd m gneti properties of r reEe rth o ltitesF9D snorg ni hemistryFD ST @IAF ppF TPUETQQF Further information on publisher's website:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Inorganic Chemistry, copyright c 2016 American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see https://doi.org/10.1021/acs.inorgchem.6b02557. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe series of perovskite rare-earth (RE) doped cobaltites (RE)CoO3 (RE = La -Dy) was prepared by microwave-assisted synthesis. The crystal structure undergoes a change of symmetry depending on the size of the RE cation. LaCoO3 is rhombohedral, S.G. , while for the rest of the RE series (Pr -Dy) the symmetry is orthorhombic, S.G. Pnma (No. 62). The crystal structure obtained by X-Ray diffraction was confirmed by high resolution transmission electron microscopy, which yielded a good match between experimental and simulated images. It is further shown that the well-known magnetism in LaCoO3, which involves a thermally induced Co 3+ (d 6 ) low spin to intermediate or high spin state transition, is strongly modified by RE-doping and a rich variety of magnetic order has been detected across the series.

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“…The magnetic properties of the compounds in medial concentration range (0.25 < x < 0.7) modify from cluster spin‐glass to spin‐glass (Fig. 1) with Fe content as it was discussed in 11. The characteristic temperature of magnetic clusters blocking is about 75 K. The magnetic properties of the compounds with concentration x > 0.7 are specific for antiferromagnetic materials with certain amount of spontaneous magnetization.…”

Section: Resultsmentioning

confidence: 81%

“…It was argued earlier 9, 11 that initial compound Pr 0.5 Sr 0.5 CoO 3− d is nearly oxygen stoichiometric with metallic‐type conductivity and interactions between Co 3 –Co 4+ ions promote ferromagnetism. A substitution of Co ions for Fe ones reduces ferromagnetic interactions as well as conductivity and the solid solutions x > 0.25 become insulators 11. A doping with Fe ions has the same effects on magnetism and conductivity for La 0.5 Sr 0.5 Co 1− x Fe x O 3 and Pr 0.55 Ca 0.45 Co 1− x Fe x O 3 systems 13, 14.…”

Section: Resultsmentioning

confidence: 98%

Magnetic peculiarity and crystal structure of Pr_0.5 Sr_0.5 Co_1−x Fe_x O₃

Karpinsky

Troyanchuk²,

Chobot

et al. 2009

phys. stat. sol. (b)

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Crystal structure and magnetic properties of the Pr 0.5 Sr 0.5 Co 1Àx Fe x O 3Àd are studied to clarify an origin of the magnetic peculiarity observed for Pr 0.5 Sr 0.5 CoO 3Àd compound near T A % 120 K. A correlation between crystal symmetry, magnetic structure, and the magnetic anomaly is discussed. At room temperature the compounds with x < 0.67 have orthorhombic crystal structure described by Imma space group. Crystal symmetry of these compounds reduces down to monoclinic (triclinic) one with a temperature decrease, whereas the crystal structure of the solid solutions with x > 0.7 remains orthorhombic at low temperatures. Increase of Fe percentage changes the magnetic properties of the compounds from ferromagnetic to cluster spin-glass, spin glass and then to antiferromagnetic one. An existence of the magnetic feature is strongly dependent on the magnetic state of the compounds. The data obtained specify that a rearrangement of the bond lengths in rare-earth sublattice is responsible for the crystal structure modification and thus for the magnetic anomaly.

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Positive magnetoresistance effect in rare earth cobaltites

Cited by 7 publications

References 16 publications

First-order magnetic phase transition in layered Sr3YCo4O10.5 + δ-type cobaltites

First-order magnetic phase transition in layered Sr3YCo4O10.5 + δ-type cobaltites

Microwave-Assisted Synthesis, Microstructure, and Magnetic Properties of Rare-Earth Cobaltites

Magnetic peculiarity and crystal structure of Pr_0.5 Sr_0.5 Co_1−x Fe_x O₃

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Positive magnetoresistance effect in rare earth cobaltites

Cited by 7 publications

References 16 publications

First-order magnetic phase transition in layered Sr3YCo4O10.5 + δ-type cobaltites

First-order magnetic phase transition in layered Sr3YCo4O10.5 + δ-type cobaltites

Microwave-Assisted Synthesis, Microstructure, and Magnetic Properties of Rare-Earth Cobaltites

Magnetic peculiarity and crystal structure of Pr0.5 Sr0.5 Co1−x Fe x O3

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Magnetic peculiarity and crystal structure of Pr_0.5 Sr_0.5 Co_1−x Fe_x O₃