Spin glass behavior in nanogranular La0.25Ca0.75MnO3 manganites

The magnetic properties of two nanogranular La0.25Ca0.75MnO3 manganites with different average grain sizes have been studied. Besides the well-known exchange bias effect and the appearance of ferromagnetic clusters in the grains of both samples, the results show the occurrence of an antiferromagnetic transition and spin glass properties. Both samples are described as core shell magnetic systems, whose main difference is found in the interface between the outer ferromagnetic and the inner antiferromagnetic phases of the grains. (C) 2014 Elsevier B.V. All rights reserved.