High-pressure synthesis and characterization of BiCu{sub 3}(Mn{sub 4−x}Fe{sub x})O{sub 12} (x=0, 1.0, 2.0) complex perovskites

Journal Article · Thu Aug 15 00:00:00 EDT 2013 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2013.05.011· OSTI ID:22274023

Martínez-Lope, M. J.; Alonso, J. A. ^[1]; Sánchez-Benítez, J. ^[2]; Fernández, M. T. ^[3]

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1. Instituto de Ciencia de Materiales de Madrid, C.S.I.C., Cantoblanco E-28049, Madrid 28049 (Spain)
2. Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense, 28040 Madrid (Spain)
3. Institut Laue Langevin, BP 156X, Grenoble F-38042 (France)

We have studied the series of nominal composition BiCu{sub 3}(Mn{sub 4−x}Fe{sub x})O{sub 12} (x=0, 1.0, 2.0) where Mn is replaced by Fe cations in the ferrimagnetic perovskite BiCu{sub 3}Mn{sub 4}O{sub 12}. These compounds have been prepared from citrate precursors under moderate pressure conditions (3.5 GPa) and 1000 °C in the presence of KClO{sub 4} as oxidizing agent. All the samples have been studied by x-ray and neutron powder diffraction (NPD) at room temperature and 4 K. The crystal structure has been defined in a cubic Im3{sup ¯} (No. 204) space group with a 2a{sub 0}×2a{sub 0}×2a{sub 0} unit-cell. The doubling of the unit-cell occurs due to the ordering of Bi{sup 3+} and Cu{sup 2+} cations over A sites of the AA′{sub 3}B{sub 4}O{sub 12} structure. The A-site accommodates 12-fold coordinated Bi{sup 3+} ions and, at the A′-site, Jahn–Teller Cu{sup 2+} ions form pseudo-square planar units aligned perpendicular to each other. Mn{sup 4+}/Fe{sup 3+} cations randomly occupy the centre of slightly distorted octahedra. These materials have also been characterized by magnetic and magnetotransport measurements. We found that all the samples are ferrimagnetic and show a progressive decrease of T{sub C} as the Fe content increases, since Fe ions disturb the ferromagnetic interactions within the B magnetic sublattice. In fact, the Curie temperature diminishes from T{sub C}=360 K (x=0) to T{sub C}=219 K (x=2). The magnetic structures, studied by low-temperature NPD data, correspond to an antiferromagnetic arrangement of spins at 8c and 6b sites; the ordered moments are in excellent agreement with those obtained from the saturation magnetization at 4 K. A significant magnetoresistant effect is determined for the x=1.0 oxide, with low-field values as high as 5% at 300 K and 1 T. Highlights: • BiCu{sub 3}(Mn{sub 4−x}Fe{sub x})O{sub 12} perovskites have been prepared under high pressure conditions. • They have been characterized by NPD, magnetic and magnetotransport measures. • The introduction of Fe leads to a transition from metallic to semiconducting. • Curie temperature decreases as the Fe content increases.

• OSTI ID: 22274023
• Journal Information: Journal of Solid State Chemistry, Vol. 204; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANTIFERROMAGNETISM
BISMUTH IONS
CATIONS
COPPER IONS
CUBIC LATTICES
CURIE POINT
INTERACTIONS
IRON IONS
MAGNETIZATION
MAGNETORESISTANCE
MANGANESE IONS
NEUTRON DIFFRACTION
OXIDES
PEROVSKITE
POTASSIUM PERCHLORATES
PRESSURE RANGE MEGA PA 10-100
SPACE GROUPS
SYNTHESIS
X RADIATION