Studium změn ve spintonických strukturách vyvolaných femtosekunovými laserovými pulzy

Farkaš, Andrej

This thesis is focused on a detailed investigation of the optically induced quench switching effect in different films of antiferromagnetic CuMnAs. The quench switching effect was recently discovered to be highly reproducible resistance switch- ing, which can be excited by electrical and optical laser pulses. This thesis com- pares the amplitude response to laser-induced quench switching for samples on the different substrate material, samples with different stoichiometries, and sam- ples with different thicknesses of CuMnAs film. The effects of different ratios between the laser spot and the size of the measured device are investigated, and position-dependent measurements are also presented. It is shown that resistivity change with optical excitation using a single 120 femtosecond laser pulse can, in ideal conditions, reach up to 15% at room temperature, which is comparable with the maximum signal obtained with electrical pulses. All of the measure- ments combined with current knowledge of quench switching illustrate the robust behavior of this mechanism across a wide range of conditions. 1

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