Structural correlations in La0.7Pb0.3(Mn1−xFex)O3 manganites as probed by small-angle and polarized neutron diffraction

Abstract

Small-to-medium-angle neutron diffraction as well as a fullneutron polarization study of CMR manganites of general formulaLa0.7Pb0.3(Mn1−xFex)O3,from x = 0 up to x = 0.2, reveal the presence of nanometre-sized magnetic domains having characteristic dimensionsabout one order of magnitude smaller than the crystal grain sizes. The role played by suchentities as main drivers of the magnetic ordering transition is established hereby analysis of the diffraction data. The model employed is then validated fromdata derived from polarized neutron diffraction. The latter also provides a directinsight into the presence of antiferromagnetic regions that arise as a consequence ofcompeting interactions brought about by Fe substitution on the Mn site. The resultsare finally discussed within the context of recent findings on related materials.