Towards the terahertz frequency measurement of the Inverse Spin Hall Effect*

The Inverse Spin Hall Effect (ISHE) has become an important tool in the spintronics field as a promising route for generation and detection of spin currents via charge currents. In particular, when the magnetization of a ferromagnet is resonantly excited by a radio-frequency field, angular momentum can be transferred to a non-magnetic metal to produce a pure spin current (spin-pumping), and the ISHE provides a way to measure the generated spin current in the metal and extract essential spin pumping parameters. Very recently, theoretical predictions of spin pumping from an antiferromagnetic (AF) insulator to a normal metal have attracted significant interest. We will report results of experiments where terahertz pulses of electromagnetic radiation resonantly excite the AF resonance on the AF insulator NiO coupled with a thin film of Pt, and attempt to measure the ISHE voltage at terahertz frequencies.