We report a first-principles density-functional study of interlayer exchange coupling (IEC) in one-dimensional Fe/Pt multilayered nanowire. The magnetic moment of the interfacial Fe atom in the Fe/Pt multilayered nanowire is found to be higher than that of the Fe atom away from the interface. A mechanism based on multistep electron transfer between the layers and spin flip within the layer is proposed to explain the magnetic-moment enhancement at the interface. The calculated IEC and magnetoresistance are found to switch signs as the width of the nonmagnetic Pt spacer varies. Depending on the width of the Pt spacer, the competition among short- and long-range direct exchanges, indirect Ruderman-Kittel-Kasuya-Yosida exchange, and superexchange is found to be responsible for the nonmonotonous feature in IEC
