Thin-film encapsulation of the air-sensitive organic-based ferrimagnet vanadium tetracyanoethylene

摘要

The organic-based ferrimagnet vanadium tetracyanoethylene (V[TCNE]_(x～2)) has demonstrated potential for use in both microwave electronics and spintronics due to the combination of high temperature magnetic ordering (T_C ＞ 600 K), extremely sharp ferromagnetic resonance (peak to peak linewidth of 1 G), and low-temperature conformal deposition via chemical vapor deposition (deposition temperature of 50 ℃). However, air-sensitivity leads to the complete degradation of the films within 2h under ambient conditions, with noticeable degradation occurring within 30 min. Here, we demonstrate encapsulation of V[TCNE]_(x～2) thin films using a UV-cured epoxy that increases film lifetime to over 710 h (30 days) as measured by the remanent magnetization. The saturation magnetization and Curie temperature decay more slowly than the remanence, and the coer-civity is unchanged after 340 h (14 days) of air exposure. Fourier transform infrared spectroscopy indicates that the epoxy does not react with the film, and magnetometry measurements show that the presence of the epoxy does not degrade the magnetic properties. This encapsulation strategy directly enables a host of experimental protocols and investigations not previously feasible for air-sensitive samples and lays the foundation for the development of practical applications for this promising organic-based magnetic material.