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.

*The work is supported by the US-NSF through contract \# DMR-0907197 (UConn) and DMR-0706610 (NIU).

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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