Network interactions and dynamical phenomena in magnetic oxides

Abstract

We have obtained a series of magnetic oxides based on manganese with remarkable magnetic properties at low temperatures. We associate the magnetic effects to three networks of local magnetic moments that interact to form the magnetization behaviour. The samples have general formula RE(CoxMn1 x)O3 (RE ¼ Gd or Er). The RE sublattice can interact with the local field imposed by the other networks. Its orientation differs depending on the RE nature, resulting in a reversal of the magnetic moment (spin inversion) during thermal cycling. Also, dynamic effects on the hysteresis loops are seen, where a sudden change of the magnetization is triggered by dH/dt. Whenever spin inversion is seen, the branches of the hysteresis loop cross at low fields; this effect disappears once the compensation temperature is reached.