  We have observed distinct temperature-dependent magnetization reversal modes
in a perpendicular (Co/Pd)4/Co/Cu/(Co/Ni)4/Co pseudo-spin-valve, which are
correlated with spin-transport properties. At 300 K, magnetization reversal
occurs by vertically correlated domains. Below 200 K the hysteresis loop
becomes bifurcated due to laterally correlated reversal of the individual
stacks. The magnetic configuration change also leads to higher spin disorders
and a significant increase in the giant magnetoresistance effect. First order
reversal curve measurements reveal that the coupled state can be re-established
through field cycling, and allow direct determination of the interlayer
coupling strength as a function of temperature.
