Magnetic relaxation behaviour in the systems Sr1 +xLa1 –x Fe1 –xSnxO4 and SrLaFe1 –xGaxO4 by Mössbauer spectroscopy and magnetometry

Abstract

The effects of magnetic dilution on the magnetism in the two-dimensional (2D) oxide systems Sr_{1 +x}La_{1 –x} Fe_{1 –x}Sn_xO₄ and SrLaFe_{1 –x}Ga_xO₄ have been studied by Mössbauer spectroscopy and magnetometry. The end-member, SrLaFeO₄, has a Néel temperature (T_N) of 330 K, and shows some degree of magnetic relaxation for T/T_N > 0.9. Diamagnetic substitution results in increased relaxation at concentrations where magnetic percolation is still effective. The magnetic susceptibility shows pronounced hysteresis effects. The possible role of the inter-planar interactions in determining the magnetic behaviour of these materials is discussed.