Magnetic properties of zinc-blende Cd1−xFexS nanoparticles: Temperature and Fe-content dependence studies

Magnetic properties of zinc-blende Cd1−xFexS (x~0.0017-0.033) nanoparticles have been investigated at various temperature regimes and contents of Fe3+ ions. The high temperature (range: 160-300 K) inverse magnetic susceptibility has been found to follow linear Curie-Weiss equation for all compositions of samples with monotonic variation of Curie-Weiss temperature, Θ (from negative to positive values) with increase in Fe3+ content, which implies a transition from anti-ferromagnetic to ferromagnetic ordering. However, at low temperature regime (range: 5-70 K) anti-ferromagnetic ordering prevails in all compositions of samples but show changing trend from anti-ferromagnetic towards ferromagnetic with Fe content, similar to the high temperature regime. A particular content of Fe3+ ions in Cd1−xFexS is estimated by fitting Θ linearly as a function of x, where identical magnetic phases are expected in both low and high temperature regimes. The sample with such amount of Fe3+ ions content has been found to be weakly anti-ferromagnetic.