Electronic transport induced ultrafast magnetization switching

The control of magnetization, and thus spin, at the shortest timescale, is of prime importance for the development of faster and energy efficient spintronic devices for memory, storage and logic. Direct femtosecond laser pulses have shown their capability to encode information on a large variety of magnetic metals. In this short review, we discuss different methods to generate ultra-short electronic excitations that can be used to induce a magnetization reversal. First, we present results obtained using photo-conductive switches which can generate pico-second electrical current pulses. Those current pulses can produce Oersted field pulses, heat pulses or induce spin torques to switch magnetization. Secondly, we discuss how thin film heterostructures can be engineered to generate polarized or unpolarized electronic (heat) transport on the femtosecond scale (i.e. hot electron pulses). These pulses can then be used to induce magnetization switching in ferrimagnetic or ferromagnetic layers via ultrafast heating and/or spin injection. These complementary methods enable us to study spintronic phenomena at ultrafast timescales.