Journal of Low Temperature Physics

, Volume 117, Issue 3–4, pp 849–853 | Cite as

A Study of Structure, Electric and Magnetic Properties of the New Layered Cobalt Oxides Sr2Y1-xCaxCo2O7-z

  • K. Yamaura
  • Q. Huang
  • R.W. Erwin
  • J.W. Lynn
  • R.J. Cava

Abstract

The crystal structure of Sr2Y0.8Ca0.2Co2O6is orthorhombic below 270 K (Immm, a = 3.84029(7) Å, b = 3.80691(6) Å and c = 19.4980(3) Å at 20 K), transformed from tetragonal (I4/mmm, a = 3.82765(6) Å and c = 19.5795(3) Å) at 295 K. The crystal structure distortion is accompanied by an anomalous temperature dependence of the degree of buckling of the CoO2plane and is correlated with the development of anisotropic antiferromagnetic ordering of magnetic moments (2.93(2) μBper Co at 20 K). A magnetically glassy state below about 35 K and variable range hopping conduction below about 64 K for\(\begin{gathered} Sr_2 Y_{1 - x} Ca_x Co^{3.4 + } _2 O_{7 - z} (0.2 \leqslant x \leqslant 0.5,0.21 \leqslant z \leqslant 0.38) \hfill \\ \hfill \\ \end{gathered} \)were found by magnetic susceptibility and electrical resistivity measurements.

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Copyright information

© Plenum Publishing Corporation 1999

Authors and Affiliations

  • K. Yamaura
    • 1
  • Q. Huang
    • 2
    • 3
  • R.W. Erwin
    • 2
  • J.W. Lynn
    • 2
  • R.J. Cava
    • 1
  1. 1.Department of Chemistry andPrinceton Materials Institute, Princeton UniversityPrincetonUSA
  2. 2.NIST Center for Neutron Research, National Institute of Standards and TechnologyGaithersburgUSA
  3. 3.Department of Materials and Nuclear EngineeringUniversity of MarylandCollege ParkUSA

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