Antiferromagnetic ordering in magnetic ionic liquid Emim[FeCl(4)]

Abstract

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 TN≈3.8 K. In addition, the shape of the magnetic ordering depends on the cooling speed, indicating that the magnetic coupling could be modified.