Physica B: Condensed Matter, Vol. 289-290 (1-4) (2000) pp.
89-93
© 2000 Elsevier Science B.V. All rights reserved.
PII:
S0921-4526(00)00269-6
A µSR study of high
oxidation state iron oxides displaying large magnetoresistance
I.M. Marshall a
*
i.marshall1@physics.ox.ac.uk,
S.J. Blundell a,
A. Husmann a,
Th. Jestädt a,
B.W. Lovett a,
F.L. Pratt b,
J. Lago c,
P.D. Battle c
and M.J. Rosseinsky c
a Clarendon Laboratory, University of Oxford, Parks Road,
Oxford OX1 3PU, UK
b RIKEN-RAL, Rutherford
Appleton Laboratory, Chilton, Oxon OX11 0QX, UK
c
Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford
OX1 3QR, UK
Abstract
The magnetic and conducting properties of many transition metal oxides may be
drastically altered by doping. This study concerns a family of compounds with
compositions intermediate between the itinerant helical antiferromagnet SrFeO3 and the
ferromagnetic metal SrCoO3. We have measured
the temperature-dependent muon-spin relaxation in five compounds in the family
SrFe1
xCoxO3 where Co substitution
varies from x=0 to 0.2 and investigated the relation between the
relaxation rate and the magnetic susceptibility above the ordering temperature.
These materials show large magnetoresistance which may be associated with the
presence of competing interactions and non-equilibrium behaviour due to cluster
formation. We find a quasistatic local field at the muon site below the magnetic
transition temperature indicative of magnetic order in samples with
x=0.15 and 0.2 but not in the sample with x=0.
Keywords:
Magnetic oxides; Magnetoresistance; Spin dynamics
*Corresponding author. Fax: +44-1865-272400
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2000, Elsevier Science, All rights reserved.