Quintuple perovskites Ln2Ba3Fe5-xCoxO15-δ (Ln = Sm, Eu) Nanoscale ordering and unconventional magnetism

A.K. Kundu (1) , O.I. Lebedev (1) , N.E. Volkova (2) , M.M. Seikh (3) , V. Caignaert (1) , V.A. Cherepanov (2) , B. Raveau (1)

1 CRISMAT - Laboratoire de cristallographie et sciences des matériaux
2 UrFU Institute of Natural Sciences and Mathematics
3 Department of Chemistry, Visva Bharati University

Quintuple perovskites Ln2Ba3Fe5-xCoxO15-δ, with Ln = Sm, Eu have been synthesized for x values varying from 0 to 2. The HRTEM and HAADF investigations show that these oxides are ordered at the nanoscale with a tetragonal "ap × ap × 5ap" lattice, corresponding to an ordered fivefold stacking of the Ba and Ln layers. These structures are in fact chemically twinned, so that only cubic or pseudo-cubic symmetry is detected by XRD investigation. The detailed magnetic study shows the existence of short range antiferromagnetic ordering, canted in nature in the temperature range from 5 to 330 K. This particular behavior is interpreted on the basis of local antiferromagnetic M-O-M (M = Fe/Co) interactions within the nanodomains that are limited by pinning of the Co/Fe spins at the boundaries. © The Royal Society of Chemistry.

Mots clés: Temperature range; X-values; Antiferromagnetism; Europium; Nanomagnetics; Nanotechnology; Perovskite; Antiferromagnetic orderings; Antiferromagnetics; Cubic symmetry; Magnetic studies; Nano domain; Nano scale

Domaines: Chimie; Cristallographie; Matériaux; Chimie théorique et/ou physique

A.K. Kundu, O.I. Lebedev, N.E. Volkova, M.M. Seikh, V. Caignaert, et al.. Quintuple perovskites Ln2Ba3Fe5-xCoxO15-δ (Ln = Sm, Eu) Nanoscale ordering and unconventional magnetism. Journal of Materials Chemistry C, 2015, 3 (21), pp.5398-5405. ⟨10.1039/c5tc00494b⟩. ⟨hal-02184155⟩