Incorporation of Jahn-Teller Cu(2+) Ions into Magnetoelectric Multiferroic MnWO4: Structural, Magnetic, and Dielectric Permittivity Properties of Mn1-xCuxWO4 (x ≤ 0.25).
Polycrystalline samples of Mn1-xCuxWO4 (x ≤ 0.5) have been prepared by a solid-state synthesis as well as from a citrate synthesis at moderate temperature (850 °C). The goal is to study changes in the structural, magnetic, and dielectric properties of magnetoelectric type-II multiferroic MnWO4 caused by replacing Jahn-Teller-inactive Mn(2+) (d(5), S = 5/2) ions with Jahn-Teller-active Cu(2+) (d(9), S = 1/2) ions. Combination of techniques including scanning electron microscopy, powder X-ray and neutron diffraction, and Raman spectroscopy demonstrates that the polycrystalline samples with low copper content 0 ≤ x ≤ 0.25 are solid solution that forms in the monoclinic P2/c space group. Rietveld analyses indicate that Cu atoms substitutes for Mn atoms at the Mn crystallographic site of the MnWO4 structure and suggest random distributions of Jahn-Teller-distorted CuO6 octahedra in the solid solution. Magnetic susceptibility reveals that only 5% of Cu substitution suppresses the nonpolar collinear AF1 antiferromagnetic structure observed in pure MnWO4. Type-II multiferroicity survives a weak Cu substitution rate (x < 0.15). Multiferroic transition temperature and Néel temperature increase as the amount of Cu increases. New trends in some of the magnetic properties and in dielectric behaviors are observed for x = 0.20 and 0.25. Careful analysis of the magnetic susceptibility reveals that the incorporation of Cu into MnWO4 strengthens the overall antiferromagnetic interaction and reduces the magnetic frustration.
Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS UMR 6502 , 2 rue de la Houssinière, F-44300 Nantes, France.
Pascaline
P
Patureau
CNRS, ICMCB UPR 9048, F-33600 Pessac, France.
Michaël
M
Josse
Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS UMR 6502 , 2 rue de la Houssinière, F-44300 Nantes, France.
Rémi
R
Dessapt
Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS UMR 6502 , 2 rue de la Houssinière, F-44300 Nantes, France.
Jean-Yves
JY
Mevellec
Laboratoire Léon Brillouin, CEA Saclay, CNRS UMR12 , F-91191 Gif-sur-Yvette, France.
Florence
F
Porcher
CNRS, ICMCB UPR 9048, F-33600 Pessac, France.
Mario
M
Maglione
Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS UMR 6502 , 2 rue de la Houssinière, F-44300 Nantes, France.
Philippe
P
Deniard
Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS UMR 6502 , 2 rue de la Houssinière, F-44300 Nantes, France.
Christophe
C
Payen