The Er(Co,Mn)O3 solid solution, in which the Mn atom has been substituted by Co has shown very interesting magnetic features, for instance, a step-like transition at high fields with increasing magnetic field, while the increasing and decreasing branches of the magnetization loops intersect in the low field region. These perovskites can be described as ferrimagnetic, where the ferromagnetic Mn/ Co lattice is oriented in opposite direction to the Er moments. These phenomena are especially evident for ErCo0.5Mn0.5O3 where ferromagnetic interactions are maximized and, at the same time, a magnetization reversal is observed. In this work, we have prepared the Er1 xYxCo0.5Mn0.5O3 (0.0pxp1.0) solid solution to sweep the strength of the magnetic moment at the rare-earth site. The more we replace Er by Y, the smaller becomes the average magnetic moment at the rare-earth site. All samples have orthorhombic structure (S.G. Pbnm) and the lattice parameter do not show significant variation when the Er is replaced by Y, so the remarkable differences seen on magnetic properties along the series are not related to changes in the structure. This systems goes from ferrimagnetic (with magnetization reversal) for x ¼ 0 (ErCo0.5Mn0.5O3) to normal ferromagnetic behavior for x ¼ 1 (YCo0.5Mn0.5O3). As the amount o yttrium increases, the remanent magnetization increases, the transition field decreases and the spin inversion gets weaker. Other important point to remark is that the magnetic transition has a dynamical component. r 2008 Elsevier B.V. All rights reserved.

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