Abstract
Amorphous
Fe
x
Ge
1
−
x
films with different metal volume fractions
(
0.40
<
x
<
1.00
)
and film thicknesses
4
-
300
nm
were fabricated by a cosputtering method. Magnetic and magnetotransport measurements indicated that the Fe-Ge films are ferromagnetic even above room temperature. A Hall sensitivity as large as
82
V
∕
AT
was obtained in the
Fe
0.67
Ge
0.33
film with a thickness of
4.1
nm
. More importantly, it was found that the Hall sensitivity does not depend on the temperature in the temperature range of
50
-
300
K
. In addition, the Hall resistance depends linearly on the magnetic field within the range of
−
2.5
-
2.5
kOe
. This linear dependence, the larger sensitivity, and its temperature independence indicate that Fe-Ge films are potential material candidates for field sensors in a very broad temperature range.