Efficient thermal spin injection using CoFeAl nanowire

Takashi Kimura from Kyushu University in Japan and colleagues have developed an ferromagnetic alloy for generating spin current without using electric fields. The researchers found that the Seebeck coefficient — a measure of how temperature changes can create electric voltages — of their ferromagnetic, iron-cobalt-aluminum alloy strongly depends upon the spin states in the alloy. By assembling this material into a nanoscale spintronic device then subjecting the device to a temperature gradient, the subsequent heat flow produced a thermal spin injection current 100 times greater than seen in typical magnets. This activity is particularly appealing because thermal spin generators are self-powered, wireless and can work in combination with conventional electric spin currents to boost the efficiency of nanoscale spintronic circuits.