  Ferromagnetic films of L10-ordered MnGa have shown promise not only in the
applications in ultrahigh-density magnetic recording and spintronic memories,
oscillators, and sensors, but also in controllable studies of novel electrical
transport phenomena. However, the stability of MnGa in chemicals and oxygen
plasma that are commonly used in the standard micro-/nano-fabrication process
has unsettled. In this work, we report a systematic study on the chemical
stability of the MnGa films in acids, acetone, ethanol, deionized water,
tetramethylammonium hydroxide (TMAOH) and oxygen plasma. We find that MnGa is
very stable in acetone and ethanol, while can be attacked substantially if
soaked in TMAOH solution for sufficiently long time. Deionized water and acids
(e.g., HCl, H3PO4 and H2SO4 solutions) attack MnGa violently and should be
avoided whenever possible. In addition, oxygen plasma can passivate the MnGa
surface by oxidizing the surface. These results provide important information
for the fabrication and the integration of MnGa based spintronic devices.
