Canted ferrimagnetism in the distorted double perovskite La3Mn2NbO9

The synthesis, structural characterization, and magnetic properties of La3Mn2NbO9 double perovskite are reported. The crystal structure has been refined by X-ray and neutron powder diffraction data in the monoclinic space group P2(1/n). The Mn2+, Mn3+ and Nb5+ cations are distributed at the 2d and 2c Wyckoff sites, with a high cation order degree in the latter, mainly occupied by Mn2+/Mn3+. The Mn3+ presence was established from X-ray Emission Spectroscopy and X-ray Photoelectron Spectroscopy. Rietveld refinements of powder neutron diffraction data show that at room temperature the cell parameters are a = 5.6063(3) angstrom, b = 5.8155(3) angstrom, c = 7.9877(2) angstrom y beta = 89.89(1)degrees. Magnetization measurements indicate the presence of ferromagnetic and antiferromagnetic interactions with T-C-19 K and T-N-11 K, respectively, with a magnetic cell of symmetry Gamma(1)(A(g)). The analysis of the neutron data suggests a canted ferrimagnetic spin structure where an antiferromagnetic unit-cell in a and c axis, and ferromagnetic in b axis with a propagation vector k = (0 1/2 0) was used. The effective magnetic moment obtained experimentally is mu(eff) = 5.50 mu B/mol Mn2+/(3+), slightly lower than the theoretical one for spin only (5.83 mu B). (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study reports the synthesis, structural characterization, and magnetic properties of La3Mn2NbO9 double perovskite. The crystal structure shows a high degree of cation order and magnetization measurements reveal the presence of ferromagnetic and antiferromagnetic interactions at different temperatures.