Magnetic properties of misfit layer compounds [((Pb,M)S)1.5]1+xNbS2;: M = Fe or (Mn,Nb)

We present magnetic properties of the recently reported 2D-misfit layer compounds [((Pb,M)S)(1.5)](1+x)NbS2 for M = Fe or (Mn,Nb). For both the title compounds, the antiferromagnetic interactions are strong. Consequently, the linear variation of the inverse magnetic susceptibilities versus temperature cannot be interpreted by a Curie-Weiss law (chi = C / (T - theta)) in the investigated temperature range. In the iron compound, an antiferromagnetic transition is observed at 25 K with a large magnetic hysteresis between the zero field cooled and field cooled susceptibilities. Magnetic frustration could explain this anomalously low transition temperature. The antiferromagnetic interactions in the manganese compound are smaller, as no transition is observed down to 2 K. (C) 2001 Elsevier Science B.V. All rights reserved.