We present measurements of current perpendicular magnetoresistance of NiMnS
b/Cu/NiMnSb spin-valve structures based upon the predicted half-metallic(10
0% spin polarized) ferromagnetic alloy NiMnSb. The observed effect of 5-10%
is much smaller than the complete spin-valve effect expected from a 100% s
pin-polarized system. The dependence of the magnetoresistance on film thick
ness and deposition parameters are explored to understand the factors limit
ing giant magnetoresistance in these structures. (C) 1999 Elsevier Science
B.V. All rights reserved.