Self-assembly of 1D FeSe2 chains and Fe(dien)2 complexes for ferrimagnetic inorganic-organic hybrid cuboids

Challenges still remain in producing room-temperature ferromagnetism/ferrimagnetism in inorganic-organic hybrid compounds. Here, we report the Fe vacancy-doped inorganic-organic (FexSe(2))(2)Fe(dien)(2) (dien = diethylenetriamine, x = 0.86) hybrid cuboids by self-assemble of finite one-dimensional (1D) FeSe2 chains and Fe (dien)(2) complexes. A growth model is proposed by kinetically controllable syntheses of novel Fe2x+1Se4(dien)(2) hybrids. The Rietveld refinement reveals that Fe vacancies in the Fe2.71Se4(dien)(2) hybrid cuboids induce large distortions of the FeSe2 chains and the room-temperature lattice parameters are a = 9.225(4) angstrom, b = 18.021(8) angstrom and c = 11.609(6) angstrom. Magnetic measurements and electron spin resonance spectra of the Fe2.71Se4(dien)(2) hybrid cuboids show the ferrimagnetism with the Curie temperature (T-C) of 600 K and the spin glass state with the freezing temperature (T-f) of 108 K. Impressive room-temperature ferrimagnetic properties of the Fe2.71Se4(dien)(2) hybrid cuboids were ascribed to the high concentration of Fe3+ vacancies (0.29 per cell) in the hybrid cuboids, which is supported by the Fe-57 Mossbauer spectrum fitting based on the ferrimagnetic model.

Automated summary

Challenges still exist in achieving room-temperature ferromagnetism/ferrimagnetism in inorganic-organic hybrid compounds. However, the Fe2.71Se4(dien)(2) hybrid cuboids exhibit impressive room-temperature ferrimagnetic properties, attributed to the high concentration of Fe3+ vacancies inducing large distortions in the FeSe2 chains.