Room-temperature ferromagnetism in transparent transition metal-doped     titanium dioxide.
Dilute magnetic semiconductors and wide gap oxide semiconductors are appealing materials for magnetooptical devices. From a combinatorial screening approach looking at the solid solubility of transition metals in titanium dioxides and of their magnetic properties, we report on the observation of transparent ferromagnetism in cobalt-doped anatase thin films with theconcentration of cobalt between 0 and 8%. Magnetic microscopy images   reveal a magnetic domain structure in the films, indicating the existence of   ferromagnetic long-range ordering. The materials remain ferromagnetic   above room temperature with a magnetic moment of 0.32 Bohr magnetons   per cobalt atom. The film is conductive and exhibits a positive   magnetoresistance of 60% at 2 kelvin.
Ceramics Materials and Structures Laboratory, Tokyo Institute of   Technology, Yokohama 226-8503, Japan.
Y
Y
Matsumoto
M
M
Murakami
T
T
Shono
T
T
Hasegawa
T
T
Fukumura
M
M
Kawasaki
P
P
Ahmet
T
T
Chikyow
S
S
Koshihara
H
H
Koinuma