Abstract
Large negative magnetoresistance (MR)
(
|
Δ
R
/
R
|
=
|
[
R
(
H
)
-
R
max
]
/
R
max
|
>
50
%
)
has been observed in the broken cold-pressed CrO
2 powder samples near the room temperature, which is ascribed to the magnetic field-induced mechanical contact variation. This large, room-temperature negative MR might easily lead to a wrong conclusion that the spin-polarization is still very high at high temperatures. This observation may also point to the possibility to develop field sensors based on the mechanical MR.