Simultaneous para-ferrimagnetic, metal-insulator, and orthorhombic-monoclinic transitions in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>YBaCo</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mrow><mml:mn>5.50</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Padilla-Pantoja, Jessica; Frontera, C.; Castaño, Óscar; García-Muñoz, J. L.

doi:10.1103/physrevb.81.132405

Cited by 13 publications

(10 citation statements)

References 31 publications

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“…Cell parameters obtained by Rietveld refinement at 300 K [a ¼ 3.82302(3) Å , b ¼ 7.85974(5) Å , c ¼ 7.52387(5) Å ] nicely agree with those found in Ref. 16 (same composition, different sample). In contrast, at T MI the orthorhombic structure gets distorted into a monoclinic (P 112=a) phase with a doubling of the a axis [a ¼ 7.70874 (6) …”

Section: Methodssupporting

confidence: 80%

“…12 This upturn coincides with the onset of the insulating regime. 12,16,19 It must be mentioned that in contrast to the Ho-based cobaltite, 12 this increase does not carry on a change in the sign of the coefficient, which is always positive in the present case (while for Ho it is negative above T MI ). By further decreasing temperature, the FM signal vanishes at T N1 % 267 K where an AFM order stabilizes.…”

Section: Methodsmentioning

confidence: 47%

“…12 However, in some compounds containing smaller rareearths (Ho,Y) the crystal cell expands when cooling across the MIT (V is larger in the insulating phase). [13][14][15][16] In these cases, the electron localization process is accompanied by an orthorhombic (above T MI ) to monoclinic crystal system change of the crystal system (below T MI ) 15,16 and the modulation of the structure. 16 Additionally, on cooling from T MI , successive magnetic transitions appear.…”

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confidence: 99%

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Spin state and structural changes at the metal-insulator transition in YBaCo2O5.5 by synchrotron x-rays

Padilla-Pantoja

Frontera

Herrero‐Martín

et al. 2012

Journal of Applied Physics

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Section: Methodssupporting

confidence: 80%

Section: Methodsmentioning

confidence: 47%

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confidence: 99%

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Spin state and structural changes at the metal-insulator transition in YBaCo2O5.5 by synchrotron x-rays

Padilla-Pantoja

Frontera

Herrero‐Martín

et al. 2012

Journal of Applied Physics

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“…x Sr = 0.05 T = 300 K T = 300 K T = 250 K T = 100 K [13]. It is also possible that a concommitant structural transition occurs to a monoclinic P 112/a space group below the metal-insulator transition temperature, as recently proposed by Malavasi et al [36] and Padilla-Pantoja et al [32] based on high-resolution synchrotron X-ray diffraction data. Our current data do not allow a refinement of the ferrimagnetic phase, but an increase in the diffracted intensity is observed at the 2θ position where the most intense magnetic reflection is to be expected, as shown in Fig.…”

Section: Structures Retained On Coolingmentioning

confidence: 96%

High-temperature behavior of Sr-doped layered cobaltites Y (Ba_{1 −x}Sr_x)Co₂O_5.5: phase stability and structural properties

Aurelio¹,

Sánchez²,

Curiale³

et al. 2010

J. Phys.: Condens. Matter

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In this paper we present a neutron diffraction in situ study of the thermal evolution and high-temperature structure of layered cobaltites Y (Ba, Sr)Co(2)O(5 + δ). Neutron thermodiffractograms and magnetic susceptibility measurements are reported in the temperature range 20 K ≤ T ≤ 570 K, as well as high-resolution neutron diffraction experiments at selected temperatures. Starting from the as-synthesized samples with δ≈0.5, we show that the room temperature phases remain stable up to 550 K, where they start losing oxygen and transform to a vacancy-disordered structure with tetragonal symmetry. Our results also show how the so-called '122' structure can be stabilized at high temperature (around 450 K) in a sample in which the addition of Sr at the Ba site had suppressed its formation. In addition, we present the structural and magnetic properties of the resulting samples with a new oxygen content δ≈0.25 in the temperature range 20 K ≤ T ≤ 300 K.

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“…The symmetry analysis forbidding the existence of noncol linear ferromagnetism in LnBaCo 2 O 5.5 was performed within the framework of the orthorhombic Pmma space group [24]. At the same time, a careful X ray structural analysis indicates that the true symmetry is monoclinic (P211/a) [25]. It is necessary to note that the true symmetry of Sr 3 YCo 4 O 10.5 + δ is also mono clinic [16] rather than orthorhombic, while the sym metry analysis in [23] was performed on the basis of the latter symmetry.…”

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confidence: 99%

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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Simultaneous para-ferrimagnetic, metal-insulator, and orthorhombic-monoclinic transitions inYBaCo2O5.50

Cited by 13 publications

References 31 publications

Spin state and structural changes at the metal-insulator transition in YBaCo2O5.5 by synchrotron x-rays

Spin state and structural changes at the metal-insulator transition in YBaCo2O5.5 by synchrotron x-rays

High-temperature behavior of Sr-doped layered cobaltites Y (Ba_{1 −x}Sr_x)Co₂O_5.5: phase stability and structural properties

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

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Simultaneous para-ferrimagnetic, metal-insulator, and orthorhombic-monoclinic transitions inYBaCo2O5.50

Cited by 13 publications

References 31 publications

Spin state and structural changes at the metal-insulator transition in YBaCo2O5.5 by synchrotron x-rays

Spin state and structural changes at the metal-insulator transition in YBaCo2O5.5 by synchrotron x-rays

High-temperature behavior of Sr-doped layered cobaltites Y (Ba1 −xSrx)Co2O5.5: phase stability and structural properties

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

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High-temperature behavior of Sr-doped layered cobaltites Y (Ba_{1 −x}Sr_x)Co₂O_5.5: phase stability and structural properties