Co-occurrence of superparamagnetism and anomalous hall effect in highly reduced cobalt-doped rutile TiO2-delta films.
We report a detailed magnetic and structural analysis of highly reduced Co doped rutile TiO(2-delta) films displaying an anomalous Hall effect (AHE). The temperature and field dependence of magnetization, and transmission electron microscopy, clearly establish the presence of nanosized superparamagnetic cobalt clusters of approximately 8-10 nm size in the films at the interface. The co-occurrence of superparamagnetism and AHE raises questions regarding the use of the AHE as a test of the intrinsic nature of ferromagnetism in diluted magnetic semiconductors.
Shinde
S R
SR
Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA. shinde@squid.umd.edu
Ogale
S B
SB
Higgins
J S
JS
Zheng
H
H
Millis
A J
AJ
Kulkarni
V N
VN
Ramesh
R
R
Greene
R L
RL
Venkatesan
T
T