A high-current, wide-band transconductance amplifier is described that provides an unprecedented level of output current at high frequencies with exceptional stability. It is capable of converting a signal voltage applied to its input into a groundreferenced output rms current up to 100 A over a frequency range from dc to 100 kHz with a useable frequency extending to 1 MHz. The amplifier has a ...

Using electron energy loss spectroscopy, we have probed the spin waves of fcc(100) cobalt after capping with 1–3 atom layers of pseudomorphic nickel or up to 12 atom layers of copper. The intensity decay of the spin wave signal is quantitatively described by the mean-free path of the incident and the scattered electron within the capping layer. The observed spin waves are therefore localized at...