Staggered Spin Order of Localized pi-electrons in the Insulating State   of the Organic Conductor kappa-BETS)2Mn[N(CN)2]3
  Magnetic properties of the conduction pi-electron system of kappa-BETS)2Mn[N(CN)2]3 have been probed using 13C NMR. At ambient pressure, the metal-insulator transition observed in the resistivity measurements below T~23K is shown to be accompanied by ordering of the pi-spins in a long-range staggered structure. As the metal-insulator transition is suppressed by applying a small pressure of ~0.5 kbar, the pi-spin system maintains the properties of the metallic state down to 5K. 
O. M. Vyaselev, M. V. Kartsovnik, N. D. Kushch, and E. B. Yagubskii
cond-mat.str-el