Magnetic spectrum of the two-dimensional antiferromagnet<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>La</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mtext>CoO</mml:mtext></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>studied by inelastic neutron scattering

Babkevich, P.; Prabhakaran, D.; Frost, C. D.; Boothroyd, A. T.

doi:10.1103/physrevb.82.184425

Cited by 32 publications

(48 citation statements)

References 27 publications

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“…This is inconsistent with the stripe-free model, which requires the fully gapped La 2 CoO 4 -type magnon spectrum in order to produce the waist and upper part of the hourglass. In addition, the magnon spectrum of Néel-ordered La 2 CoO 4 is isotropic until the spectrum approaches the zone boundary at high energies23, and therefore cannot reproduce the observed tetragonal anisotropy and 45° rotation of the intensity maxima relative to the fourfold pattern below the waist of the hourglass12.…”

Section: Discussionmentioning

confidence: 99%

Direct evidence for charge stripes in a layered cobalt oxide

et al. 2016

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Recent experiments indicate that static stripe-like charge order is generic to the hole-doped copper oxide superconductors and competes with superconductivity. Here we show that a similar type of charge order is present in La5/3Sr1/3CoO4, an insulating analogue of the copper oxide superconductors containing cobalt in place of copper. The stripe phase we have detected is accompanied by short-range, quasi-one-dimensional, antiferromagnetic order, and provides a natural explanation for the distinctive hourglass shape of the magnetic spectrum previously observed in neutron-scattering measurements of La2−xSrxCoO4 and many hole-doped copper oxide superconductors. The results establish a solid empirical basis for theories of the hourglass spectrum built on short-range, quasi-static, stripe correlations.

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Section: Discussionmentioning

confidence: 99%

Direct evidence for charge stripes in a layered cobalt oxide

et al. 2016

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“…Here, the double exchange interactions between Co 3+ and Co 4+ are playing an important role in controlling the magnetic/spin-state transitions. Also, the layered cobaltites La 2−x Sr x CoO 4 (containing both Co 2+ and Co 3+ ) are very interesting to understand the role of different spin as well as valence states of Co ions in controlling the magnetic, transport and electronic properties [35][36][37][38][39][40][41]. For example, it has been reported that the Co 2+ present mostly in HS state, whereas different spin-states are possible in Co 3+ [37,38].…”

Section: Introductionmentioning

confidence: 99%

Anomalous magnetic and spin glass behavior in Nb-substituted LaCo1−xNbxO3

Shukla

Dhaka

2018

Phys. Rev. B

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We report the structural, magnetic, transport and electronic properties of Nb substituted LaCo1−xNbxO3 (x = 0-0.2). The Rietveld analysis of x-ray diffraction data demonstrate structural phase transitions from rhombohedral to orthorhombic and further to monoclinic with increasing the Nb concentration up to x ≥ 0.2. Interestingly, we observed dramatic changes in the magnetization (M) with increasing the Nb concentration, as the M sharply increases below 10 K even at 2.5% substitution. Furthermore, ac susceptibility data show the spin-glass behavior in x = 0.1 sample. We find that the density of states near the Fermi level decreases and the activation energy increases, which results in the decreasing conductivity with higher Nb concentration. A significant shift in the peak position of A2g phonon mode has been observed using Raman spectroscopy, which indicates the change in the coupling due to the structural distortion with Nb substitution. The core-level photoemission study confirms that the Nb is present in 5+ valence state. Our study reveals that the nonmagnetic Nb 5+ (d 0 ) substitution converts Co 3+ ions to Co 2+ and stabilize both in the high-spin state. Our results suggest that structural and spin-state transitions as well as the difference in the ionic radii between Nb 5+ and Co 3+ are playing an important role in tuning the physical properties.

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“…Magnetic excitations in La 2−x Sr x CoO 4 were studied for pure La 2 CoO 4 [154], for half-doped La 1.5 Sr 0.5 CoO 4 [138,147,148] and more recently also for La 1.67 Sr 0.33 CoO 4 [152]. The magnon dispersion in the pure and in the half-doped material can be well described by linear spin-wave theory and thus allows one to determine the magnetic interaction between two neighboring Co 2+ moments J nn and that between two Co 2+ moments connected by an intermediate non-magnetic Co 3+ , J ′′ see Fig.…”

Section: (C)mentioning

confidence: 99%

Neutron scattering studies on stripe phases in non-cuprate materials

Ulbrich

Braden

2012

Physica C: Superconductivity

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Several non-cuprates layered transition-metal oxides exhibit clear evidence for stripe ordering of charges and magnetic moments. Therefore, stripe order should be considered as the typical consequence of doping a Mott insulator, but only in cuprates stripe order or fluctuating stripes coexist with metallic properties. A linear relationship between the charge concentration and the incommensurate structural and magnetic modulations can be considered as the finger print of stripe ordering with localized degrees of freedom. In nickelates and in cobaltates with K 2 NiF 4 structure, doping suppresses the nearest-neighbor antiferromagnetism and induces stripe order. The higher amount of doping needed to induce stripe phases in these non-cuprates series can be attributed to reduced charge mobility. Also manganites exhibit clear evidence for stripe phases with further enhanced complexity, because orbital degrees of freedom are involved. Orbital ordering is the key element of stripe order in manganites since it is associated with the strongest structural distortion and with the perfectly fulfilled relation between doping and incommensurability. Magnetic excitations in insulating stripe phases exhibit strong similarity with those in the cuprates, but only for sufficiently short magnetic correlation lengths reflecting well-defined magnetic stripes that are only loosely coupled.

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Magnetic spectrum of the two-dimensional antiferromagnetLa2CoO4studied by inelastic neutron scattering

Cited by 32 publications

References 27 publications

Direct evidence for charge stripes in a layered cobalt oxide

Direct evidence for charge stripes in a layered cobalt oxide

Anomalous magnetic and spin glass behavior in Nb-substituted LaCo1−xNbxO3

Neutron scattering studies on stripe phases in non-cuprate materials

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