A New Ferromagnetic Organic Semiconductor (BEDT‐TTFVS)⋅FeBr4

We present clear evidence for ferromagnetic ordering in the magnetization data of (BEDT‐TTFVS)⋅FeBr4, which was newly synthesized as a semiconducting 1:1 charge‐transfer salt. Magnetization data obtained by a resonant circuit method show a magnetic transition temperature of 1.9 ± 0.3 K, and a hysteresis loop below 1.5 K. An additional magnetization jump at 0.2 T was clearly observed below 1.9 K, suggesting that the salt does not show simple ferromagnetism but a more complicated behavior such as a canted ferromagnetism.