IOP PUBLISHING JOURNAL OF PHYSICS: CONDENSED MATTER
J. Phys.: Condens. Matter 19 (2007) 266211 (15pp) doi:10.1088/0953-8984/19/26/266211
Competition between ferromagnetism and
antiferromagnetism: origin of large magnetoresistance
in polycrystalline SrRu
1-x
Mn
x
O
3
(0 x 1)
Xiao-Yu Zhang
1,2
, Yajie Chen
3,4
, Zhen-Ya Li
1
, Carmine Vittoria
3
and
Vincent G Harris
3
1
Department of Physics and Jiangsu Key Laboratory of Thin Films, Suzhou University,
Suzhou 215006, People’s Republic of China
2
Laboratory of Solid State Microstructures, Nanjing University, Nanjing 218008,
People’s Republic of China
3
Center for Microwave Magnetic Materials and Integrated Circuits, and the Department of
Electrical and Computer Engineering, Northeastern University, Boston, MA 02115, USA
E-mail: y.chen@neu.edu
Received 23 February 2007, in final form 10 May 2007
Published 7 June 2007
Online at stacks.iop.org/JPhysCM/19/266211
Abstract
Polycrystalline SrRu
1−x
Mn
x
O
3
(0 x 1) perovskite oxides have been
prepared by a conventional solid-state reaction technique. Magnetic and
magnetotransport properties are measured using a superconducting quantum
interference device (SQUID, Quantum Design MPMS) over a temperature range
of 4–300 K. The substitution of Mn ions for Ru drives the system from a
ferromagnetic state, SrRuO
3
, to an antiferromagnetic state, SrMnO
3
, which is
basically similar to observations in single-crystal SrRu
1−x
Mn
x
O
3
(Cao et al
2005 Phys. Rev. B 71 035104). However, the measurement of dc magnetization
and ac susceptibility indicates that magnetic phase transition with x is more
complicated and pronounced than those in single crystals. The phase transition
process as temperature is reduced covers paramagnetism–antiferromagnetism
(PM–AFM), paramagnetism–ferromagnetism (PM–FM) and ferromagnetism–
cluster glass–spin glass (FM/CG/SG) etc. In particular, we observe a large low-
temperature magnetoresistance (MR) of −41% for the sample x = 0.55, which
is the largest MR measured in Mn-doped SrRuO
3
. The experiment has verified
that the large MR stems predominantly from a unique spin glass state in the
polycrystalline alloy. These results substantiate that Ru-based oxides doped
with 3d/4d transition metals have the potential for use in spintronics devices
due to their adjustable phase transition, depending upon the level and nature of
3d/4d ion doping.
4
Author to whom any correspondence should be addressed.
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