Details

Autor(en) / Beteiligte

• de Pedro, I.
• Rojo, J.M.
• Rodríguez Fernández, J.
• Sanchez Marcos, J.
• Fernández-Díaz, M.T.
• Rojo, T.

Titel

Heat capacity and neutron diffraction studies on the frustrated magnetic Co2(OH)(PO4)1−x(AsO4)x [0≤x≤1] solid solution

Ist Teil von

• Journal of solid state chemistry, 2012-04, Vol.188, p.1-10

Ort / Verlag

Amsterdam: Elsevier Inc

Erscheinungsjahr

2012

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• The Co2(OH)(PO4)1−x(AsO4)x [0≤x≤1] solid solution exhibits a complex magnetic behaviour due to the bond-frustration in its magnetic structure. Heat capacity measurements of the (x=0.1–0.5) phases show a three-dimensional magnetic ordering (λ anomaly) that shifts to lower temperatures and becomes broader as the AsO43− content increases. For x=0.75, no significant feature was observed whereas for higher arsenate ion content, x=0.9 and 1, a small maximum was detected. The magnetic structures of solid solution are consistent with the existence of predominant antiferromagnetic superexchange interactions through the |OH| and |XO4| (X=P and As) groups between the Co+2 ions. The substitution of PO43− by AsO43− anions by more than 90% substantially modifies the magnetic exchange pathways in the solid solution, leading to an incommensurate antiferromagnetic structure in Co2(OH)(PO4)1−x(AsO4)x [x=0.9 and 1] phases. Magnetic structures of Co2(OH)(PO4)1−x(AsO4)x [0≤x≤1]. The ordering of the magnetic moments of Co2+ is in c direction for the two crystallographic positions (dimers and chains) in all compounds. The unit cell is surrounded by a red line. [Display omitted] ► Synthesis of a new adamite-type compounds, Co2(OH)(PO4)1−x(AsO4)x (0.1, 0.25, 0.5, 0.75, 0.9) phases. ► Co2(OH)(PO4)1−x(AsO4)x (0–1) solid solution; magnetic frustrated system. ► High resolution neutron powder diffraction to determine the crystal structures. ► Incommensurate magnetic structures at low temperature. ► Magnetostructural correlations in cobalt-based Co2(OH)XO4 (X=P and As) insulation compounds.