Magnetic and Electrical Properties of Ordered 112-type Perovskite LnBaCoMnO5+\delta (Ln = Nd, Eu)

TL;DR

This study explores the magnetic and electrical properties of ordered 112-type LnBaCoMnO5+ oxides, revealing unique magnetic transitions and interactions influenced by Mn substitution, with implications for understanding complex magnetic behaviors in these materials.

Contribution

It provides new insights into the magnetic behavior of Mn-substituted 112-type perovskites, highlighting the effects of Mn on magnetic interactions and transitions.

Findings

NdBaCoMnO5.9 shows a paramagnetic to antiferromagnetic transition at 220 K.

EuBaCoMnO5.7 exhibits ferromagnetic regions within an antiferromagnetic matrix below 177 K.

Mn substitution suppresses ferromagnetism and introduces complex magnetic interactions.

Abstract

Investigation of the oxygen-deficient 112-type ordered oxides of the type LnBaCoMnO5+\delta (Ln = Nd, Eu) evidences certain unusual magnetic behavior at low temperatures, compared to the LnBaCo2O5+\delta cobaltites. One observes that the substitution of manganese for cobalt suppresses the ferromagnetic state and induces strong antiferromagnetic interactions. Importantly, NdBaCoMnO5.9 depicts a clear paramagnetic to antiferromagnetic type transition around 220 K, whereas for EuBaCoMnO5.7 one observes an unusual magnetic behavior below 177 K which consists of ferromagnetic regions embedded in an antiferromagnetic matrix. The existence of two sorts of crystallographic sites for Co/Mn and their mixed valence states favor the ferromagnetic interaction whereas antiferromagnetism originates from the Co3+-O-Co3+ and Mn4+-O-Mn4+ interactions. Unlike the parent compounds, the present Mn-substituted phases do not exhibit prominent magnetoresistance effects in the temperature range 75-400K.