Submicron-scale light modulation device driven by current-induced domain wall motion for electro-holography

A submicron-scale magneto-optical light modulation device driven by current-induced domain wall motion (CIDWM) was fabricated for an electro-holographic display application. The device consists of a Gd-Fe nanowire for light modulation and two Co/Pd hard magnets (HMs) with different coercivities. We succeeded in fabricating two HMs with different coercivities from a Co/Pd film by simply changing their length and realizing an anti-parallel magnetization direction configuration for the HMs, which is very important for initial domain nucleation and the CIDWM. We confirmed successful domain wall motion and light modulation when a pulse current of 0.8 mA was injected into the device, whose size was as small as 0.5 × 2 m2. The current value was lower than that required for the previously reported light modulation device driven by spin-transfer switching.