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The discovery of superconductivity in anti-PbO-type FeS has attracted great interest in the intercalation compounds of FeS. However, it is much more difficult to synthesize intercalates of FeS than to synthesize intercalates of FeSe. Here, we report a novel intercalation compound of FeS with chemical composition of (N2H4)1-xFe2+δS2 (x ​~ ​0.25, δ ​~ ​0.1), which is synthesized via a combination of self-flux solid state method and hydrothermal route. The successful intercalation of hydrazine was confirmed by X-ray diffraction, thermogravimetric analyses and attenuated total internal reflection-Fourier transform infrared spectroscopy, while the maintenance of anti-PbO-type FeS layer in the structure was verified by transmission electron microscopy and Raman spectroscopy. Magnetic and resistivity measurements show that (N2H4)1-xFe2+δS2 is a ferromagnetic metal rather than a superconductor. The low-temperature ferromagnetism may be caused by the intercalated hydrazine molecules or interlayer iron ions and the absence of superconductivity should be closely related to the ferromagnetic ordering.

Bat-borne rabies is a viral infection caused by lyssaviruses. To explore the complex interaction between bats and cattle, we develop a periodic compartment system with seasonality, temperature-dependent incubation period and different control measures. We derive the basic reproduction number R 0 and show it determines the global dynamics. In particular, we prove the non-existence of positive periodic solutions in the critical case where R 0 = 1 . Numerically, we observe that sufficient long time-varying incubation periods could potentially increase the disease outbreak risk.