Mn-Si-C alloy films are prepared by e-beam coevaporation onto a Si substrate held at 600 °C. Ferromagnetism is observed below T = (360 +/- 5) K with SQUID magnetometry and magneto-optical Kerr effect. This is the highest Curie temperature T yet observed for a Mn-based alloy. Although the composition determined by Auger depth profiling varies appreciably for different films, their T is the same indicating that ferromagnetism is caused by an alloy of well-defined composition independent of precipitations
