3 research outputs found
Ultrafast element-resolved magneto-optics using a fiber-laser-driven extreme ultraviolet light source
We present a novel setup to measure the transverse magneto-optical Kerr
effect in the extreme ultraviolet spectral range at exceptionally high
repetition rates based on a fiber laser amplifier system. This affords a very
high and stable flux of extreme ultraviolet light, which we use to measure
element-resolved demagnetization dynamics with unprecedented depth of
information. Furthermore, the setup is equipped with a strong electromagnet and
a cryostat, allowing measurements between 10 and 420 K using magnetic fields up
to 0.86 T. The performance of our setup is demonstrated by a set of
temperature- and time-dependent magnetization measurements showing distinct
element-dependent behavior
Verification of ultrafast spin transfer effects in iron-nickel alloys
Abstract The optical intersite spin transfer (OISTR) effect was recently verified in Fe50Ni50 using extreme ultraviolet magneto-optical Kerr measurements. However, one of the main experimental signatures analyzed in this work, namely a magnetic moment increase at a specific energy in Ni, was subsequently found also in pure Ni, where no transfer from one element to another is possible. Hence, it is a much-discussed issue whether OISTR in FeNi alloys is real and whether it can be verified experimentally or not. Here, we present a comparative study of spin transfer in Fe50Ni50, Fe19Ni81 and pure Ni. We conclusively show that an increase in the magneto-optical signal is indeed insufficient to verify OISTR. However, we also show how an extended data analysis overcomes this problem and allows to unambiguously identify spin transfer effects. Concomitantly, our work solves the long-standing riddle about the origin of delayed demagnetization behavior of Ni in FeNi alloys