Structural and magnetic properties of Er(Co,Mn)O3 perovskite

In this work, we present the partial substitution of Mn by Co in ErCoxMn1 xO3 manganites (0.2pxp0.7). Besides the structural changes due to a smaller tolerance factor, this perovskite system shows very interesting magnetic properties. Magnetic iso-field studies (ZFC–FC) reveal this system is ferrimagnetic, leading to a spin reversal at low temperature due to a negative exchange interaction between the two sublattices (rare-earth and transition metal ones). Furthermore, for samples near the ErCo0.5Mn0.5O3 composition, a very unusual behavior is observed when magnetization loops are performed at low temperature: a step-like transition occurs at about 4 T with increasing magnetic field, while the increasing and decreasing branches of the magnetization curves intersect in the low-field region. Neutron diffraction experiments were performed for the nominal composition (ErCo0.5Mn0.5O3) in order to study the evolution of the lattice parameters and magnetic structure at zero field in samples annealed under different atmospheres (air and oxygen). Results are discussed in relation to the presence of several magnetic entities and their respective exchange interactions. r 2007 Elsevier B.V. All rights reserved. PACS: 75.25.+z; 75.30.Et; 75.50.Gg; 75.47.Lx