Magnetic phase separation in SrCoO$_{2.5+x}$

ORAL

Abstract

We study phase separation and inhomogeneities induced by oxygen non-stoichiometry in SrCoO$_{2.5+x}$. In previous work [A. Nemudry, et. al. Chem. Mater. 8, 2232(1996)], it has been shown that as oxygen is driven into the SrCoO$_{2.5 }$electrochemically, the material structurally separates into two different phases: one is antiferromagnetic SrCoO$_{2.5}$, and the other is ferromagnetic SrCoO$_{2.75}$. We show that two distinct ferromagnetic phases appear for SrCoO$_{2.88}$ and SrCoO$_{3}$, with T$_{c}$ = 220 K and 280 K, respectively. The phase diagram of SrCoO$_{2.5+x}$ suggests the four magnetic line phases are the only stable ground states in the system. While antiferromagnetic SrCoO$_{2.5}$ is orthorhombic, the three ferromagnetic phases are pseudo-cubic and, unlike the magnetic properties, do not show the coexistence of different structures. The existence of distinct T$_{c}$=220 K and T$_{c}$=260 K magnetic phases with no structural differentiation indicates the presence of magnetic phase separation.

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Authors

  • Changkun Xie

    University of Connecticut

  • Yuefeng Nie

    University of Connecticut

  • Barrett Wells

    University of Connecticut

  • Joseph Budnick

    University of Connecticut

  • William Hines

    University of Connecticut

  • B. Dabrowski

    MSD, Argonne National Laboratory, and Physics, Northern Illinois University, De Kalb IL, USA, Physics Department, Northern Illinois University, DeKalb, IL 60115, Physics Department, Northern Illinois University, DeKalb, IL 60115 and Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, Department of Physics, Northern Illinois University, DeKalb, IL and Materials Science Division, Argonne National Laboratory, Argonne, IL, Northern Illinois University, Physics Department, Northern Illinois University, DeKalb IL 60115, Department of Physics, Northern Illinois University, DeKalb, IL 60115