Observation of magnetoconductivity with terahertz probes for ferromagnetic Fe films

Ultrafast characterization of spin-dependent transport behavior in ferromagnetic systems without contact probes has been of strong demand, recently. We have experimentally investigated spin-dependent complex conductivity for ferromagnetic Fe films of various thickness by means of terahertz time-domain transmission spectroscopy. Comparison of the transmitted terahertz wave amplitude and the spin-dependent conductivity reveals that the magnetization state of films effectively determines the complex conductivity. Non-invasive observation of spin-dependent conductivity by contact-free terahertz probe method is proven to be promising in further investigating spintronic materials, particularly on an ultrafast timescale.