The magnetic ionic liquids(MILs) are considered to open up a wide range of applications because of their magnetic and electrochromic switching. Until recently almost all magnetic ionic liquids containing tetrachloroferrate ion FeCl4- evidenced a paramagnetic temperature dependence of the magnetic susceptibility, with only small deviations from the Curie law at low temperatures. However, 1-ethyl-3-methylimidazolium tetrachloroferrate, Emim[FeCl4], clearly exhibits a long-range antiferromagnetic ordering below the Neel temperature T-N approximate to 3.8 K. In addition, the shape of the magnetic ordering depends on the cooling speed, indicating that the magnetic coupling could be modified. (C) 2010 Elsevier B.V. All rights reserved.