Room temperature spin filtering in epitaxial cobalt-ferrite tunnel barriers

• Published in: Applied physics letters Vol. 91; no. 12; pp. 122107 - 122107-3
• Main Authors: Ramos, A. V., Guittet, M.-J., Moussy, J.-B., Mattana, R., Deranlot, C., Petroff, F., Gatel, C.
• Format: Journal Article
• Language: English
• Published: American Institute of Physics 17-09-2007
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.2787880

The authors report direct experimental evidence of room temperature spin filtering in magnetic tunnel junctions (MTJs) containing
Co
Fe
2
O
4
tunnel barriers via tunneling magnetoresistance (TMR) measurements.
Pt
(
111
)
∕
Co
Fe
2
O
4
(
111
)
∕
γ
-
Al
2
O
3
(
111
)
∕
Co
(
0001
)
fully epitaxial MTJs were grown in order to obtain a high quality system, capable of functioning at room temperature. Spin-polarized transport measurements reveal significant TMR values of
−
18
%
at
2
K
and
−
3
%
at
290
K
. In addition, the TMR ratio follows a unique bias voltage dependence that has been theoretically predicted to be the signature of spin filtering in MTJs containing magnetic barriers.
Co
Fe
2
O
4
tunnel barriers therefore provide a model system to investigate spin filtering in a wide range of temperatures.