Synthesis, structure and magnetic properties of La3Co2SbO9: A double perovskite with competing antiferromagnetic and ferromagnetic interactions

• Published in: Journal of solid state chemistry Vol. 194; pp. 385 - 391
• Main Authors: Franco, D.G., Fuertes, V.C., Blanco, M.C., Fernández-Díaz, M.T., Sánchez, R.D., Carbonio, R.E.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.10.2012; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Double perovskite; Exact sciences and technology; Ferromagnetic; Ferromagnetism; Inorganic compounds; La3Co2SbO9; Long range order; Magnetic frustration; Magnetic properties; Magnetic properties and materials; Magnetization; Magnetization curves; Neutron diffraction; Neutron diffraction and scattering; Other ferromagnetic metals and alloys; Perovskites; Physics; Powder neutron diffraction; Rietveld refinement; Single-crystal and powder diffraction; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Studies of specific magnetic materials; Synthesis; Double perovskite; Powder neutron diffraction; Rietveld refinement; La3Co2SbO9; Ferromagnetic; Magnetic frustration; Antiferromagnetism; Rietveld method; Stoichiometry; SbO; Space groups; Neutron diffraction; Ferromagnetic materials; XRD; High temperature; Co; La; High field; Magnetic structure; Ferromagnetism; Magnetic materials; Magnetic properties; Crystal structure; Temperature distribution; Temperature dependence; Magnetization; Long-range order; Magnetic field effects; Magnetic moments; Perovskites; Low field; Lattice parameters; Monoclinic lattices; Powder pattern; Non linear effect; Exchange interactions
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2012.05.045

The synthesis, structural characterization, and magnetic properties of La3Co2SbO9 double perovskite are reported. The crystal structure has been refined by X-ray and neutron powder diffraction data in the monoclinic space group P21/n. Co2+ and Sb5+ have the maximum order allowed for the La3Co2SbO9 stoichiometry. Rietveld refinements of powder neutron diffraction data show that at room temperature the cell parameters are a=5.6274(2)Å, b=5.6842(2) Å, c=7.9748(2) Å and β=89.999(3)°. Magnetization measurements indicate the presence of ferromagnetic correlations with TC=55K attributed to the exchange interactions for non-linear Co2+–O–Sb5+–O–Co2+ paths. The effective magnetic moment obtained experimentally is μexp=4.38μB (per mol Co2+), between the theoretical one for spin only (3.87μB) and spin-orbit value (6.63μB), indicating partially unquenched contribution. The low magnetization value at high magnetic field and low temperature (1μB/f.u., 5T and 5K) and the difference between ZFC and FC magnetization curves (at 5kOe) indicate that the ferromagnetism do not reach a long range order and that the material has an important magnetic frustration. Co–O–Co (Yellow octahedra only) rich zones (antiferromagnetic) are in contact with Co–O–Sb–O–Co (Red and yellow octahedra) rich zones (Ferromagnetic) to give the peculiar magnetic properties, as a consequence, a complex hysteresis loop can be observed composed by a main and irreversible curve in all the measured range, superimposed with a ferromagnetic component at low fields. [Display omitted] ► La3Co2SbO9 has small Goldschmidt Tolerance Factor (t) due to the small size of La3+. ► Small t determines an angle for the path Co2+–O–Sb5+–O–Co2+ of 153°. ► Ferromagnetism is attributed to exchange interactions for Co2+–O–Sb5+–O–Co2+ paths. ► Ferromagnetic nanoclusters are embedded in an antiferromagnetic matrix.