Magnetization and susceptibility of FeCl2•H2O

High-field magnetization data in the ordered state of FeCl2 . H2O, and paramagnetic susceptibility data above T-c approximate to 20.4 K, are presented. At 10 K two not very sharp transitions are seen in M vs. H, at 0.38 and 2.14 T. As H is decreased both transitions appear at the same fields; hysteresis is modest and the remanence is near zero. At 1.6 K three sharp transitions are seen, at 2.36, 3.40 and 4.87 T; on decreasing H only one transition is seen, at 1.73 T, and both the hysteresis and remanence are large. Between 20.5 and 80 K the susceptibility can be fit by the Moriya form for weak ferromagnetism, but the overall behavior of FeCl2 . H2O is distinctly more complicated. (C) 1998 Elsevier Science B.V. All rights reserved.