Wy. Lee et al., EFFECTS OF DEPOSITION TEMPERATURE ON THE GIANT MAGNETORESISTANCE OF AS-DEPOSITED AG-CO THIN-FILMS, Journal of applied physics, 74(9), 1993, pp. 5871-5873
Giant magnetoresistance (GMR) is reported in Ag1-xCox(x=0.26-0.53) fil
ms cosputtered on Si at 28-354-degrees-C from separate Ag and Co targe
ts. GMR ratios (10 kOe maximum field) as high as 0.55 and 0.24 at 5 an
d 295 K, respectively, are achieved for the Ag0.67Co0.33 films deposit
ed at a substrate temperature, T(s), of 125-degrees-C. The GMR ratio i
ncreases slightly when the T(s) increases from 28 to congruent-to 125-
degrees-C, and decreases substantially at T(s) > 175-degrees-C. The re
sistivity of these films decreases monotonically with increasing T(s)
and levels off to a value congruent-to 3 X of Ag at T(s) greater-than-
or-equal-to 250-degrees-C. The films deposited at lower T(s) consist o
f essentially a metastable Ag-Co solid solution, while those deposited
at higher T(s) consist of separate fcc Ag and fcc Co. The coercivity
of these films increases rapidly at T(s) much greater than 125-degrees
-C, consistent with the growth of single-domain ferromagnetic Co parti
cles in this T(s) range. The T(s) dependence of GMR ratios is interpre
ted based on spin-dependent interfacial scattering arising from the T(
s) dependence of the size and number of ferromagnetic Co particles wit
hin the electron mean free path.