Anisotropic susceptibility of La2- xSrxCoO4 related to the spin states of cobalt

  title={Anisotropic susceptibility of La2- xSrxCoO4 related to the spin states of cobalt},
  author={Nils Hollmann and Maurits W. Haverkort and Matthias Cwik and M. Benomar and M. Reuther and Arata Tanaka and Thomas Lorenz},
  journal={New Journal of Physics},
We present a study of the magnetic susceptibility of La2- xSrxCoO4 single crystals in a doping range 0.3 ≤ x ≤ 0.8. Our data show a pronounced magnetic anisotropy for all compounds. This anisotropy is in agreement with a low-spin ground state (S = 0) of Co3+ for x ≥ 0.4 and a high-spin ground state (S = 3/2) of Co2+. We compare our data with a crystal-field model calculation assuming local moments and find a good description of the magnetic behavior for x ≥ 0.5. This includes the pronounced… 

Figures from this paper

Magnetic correlations in mixed valent layered La1.2Sr0.8CoO4
A possibility of high spin hole states in doped CoO2 layered systems.
It is found that such singlet pairs self-organize at higher doping into lines of magnetic ions with coexisting antiferromagnetic and ferromagnetic bonds between them, forming stripe-like structures within the investigated range of doping.
Anomalous magnetic and spin glass behavior in Nb-substituted LaCo1−xNbxO3
We report the structural, magnetic, transport and electronic properties of Nb substituted LaCo$_{1-x}$Nb$_x$O$_3$ ($x =$ 0--0.2). The Rietveld analysis of x-ray diffraction data demonstrate
Direct evidence for charge stripes in a layered cobalt oxide
The stripe phase is detected in La5/3Sr1/3CoO4, an insulating analogue of the copper oxide superconductors containing cobalt in place of copper, and provides a natural explanation for the distinctive hourglass shape of the magnetic spectrum previously observed in neutron-scattering measurements.
Griffiths-like phase and charge-spin glass state in La1.5Sr0.5CoO4
Hole-doped antiferromagnetic La2CoO4 has been known to possess intriguing electronic and magnetic phases due to the complex temperature and magnetic field dependent behavior of Co3+ ions. Here, we
Evolution of valence- and spin-specific local distortions in La2−xSrxCoO4
We present X-ray spectroscopic evidence for the evolution of valence-specific spin states and tetragonal distortions in single-layer cobaltates. Measurements of Co $L_3$-edge resonant inelastic X-ray
Relation among Oxygen Stoichiometry, Structure, and Co Valence and Spin State in Single-Layer La2-xAxCoO4±δ (A = Ca, Sr) Perovskites.
The role of oxygen stoichiometry and structural properties in the modulation of Co valence and spin state in single-layer La2-xAxCoO4±δ perovskites as well as the interplay between their local structural properties and the magnetic and charge-ordering phenomena is investigated.
Single Crystal Growth of Pure Co 3+ Oxidation State Material LaSrCoO 4
Abstract: We report on the single crystal growth of the single-layer perovskite cobaltate LaSrCoO 4 that was grown by the optical floating zone method using high oxygen pressures. Phase purity


Independent freezing of charge and spin dynamics in La1.5Sr0.5CoO4
We present elastic and quasielastic neutron scattering measurements characterizing peculiar short-range charge-orbital and spin order in the layered perovskite material La1.5Sr0.5CoO4. We find that
Intermediate-spin state and properties of LaCoO3.
The electronic structure of the perovskite LaCoO3 for different spin states of Co ions was calculated in the local-density approximation LDA+U approach and shows that Co 3d states of t(2g) symmetry form narrow bands which could easily localize, while e(g) orbitals, due to their strong hybridization with the oxygen 2p states, form a broad sigma* band.
Electronic structure and spin-state transition of LaCoO3.
The O 1s XAS spectra reflect important changes in the unoccupied Co 3d bands across the spin-state transition, and indicate a gradual transition to a mixed-spin state in LaCoO3.
Pressure-induced insulating state in (La,Sr)CoO3
We have investigated the effect of pressure on the electronic, magnetic, and structural properties on a single crystal of conducting, ferromagnet (TC=157 K) La0.82Sr0.18CoO3 located near the boundary
Evidence for a low-spin to intermediate-spin state transition in LaCoO 3
We present measurements of the magnetic susceptibility and of the thermal expansion of a LaCoO 3 single crystal. Both quantities show a strongly anomalous temperature dependence. Our data are
Theoretical study on the spin-state transition in doped La2-xSrxCoO4
The spin-state transition is an interesting and unresolved problem in layered perovskite La2-xSrxCoO4 under doping, as it involves competition among different magnetic structures. Within the
Evidence for orbital ordering in LaCoO3
We present powder and single-crystal x-ray diffraction data as evidence for a monoclinic distortion in the low-spin (S=0) and intermediate spin states (S=1) of LaCoO3. The alternation of short and
Controlling orbital moment and spin orientation in CoO layers by strain.
A quantitative model is presented to explain how strain together with the spin-orbit interaction determine the 3d orbital occupation, the magnetic anisotropy, as well as the spin and orbital contributions to the magnetic moments.