Fabrication of microstrips of iron-based superconductor NdFeAs(O,H)

NdFeAs(O,H) microstrips with line widths of about 1–5 µm were fabricated by photolithography and Ar-ion dry etching. The microstrips were fabricated under two different etching conditions: 25 min etching at a power of 20 W (long duration, low power) and 3 min etching at 100 W (short duration, high power). For both conditions, the narrowest microstrips, which were 0.9 µm in width, retained high critical temperatures of about 85% of those before microfabrication. Further, the 0.9 µm microstrip fabricated under the high-power, short-duration condition exhibited a high critical current density (Jc) of more than 4 MA cm−2 at 4 K. However, Jc of the microstrip fabricated under the low-power, long-duration condition was somewhat lower. Our analysis suggests that the edges of the microstrips were damaged more than twice as wide as those of the microstrips fabricated under the high-power, short-duration condition. This indicates that a short duration is more effective to reduce the damage than using a lower etching power.