Structural and magnetic properties of the ordered perovskite Pb2CoTeO6
2010 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 39, no 46, 11136-11148 p.Article in journal (Refereed) Published
The complex perovskite Pb2CoTeO6 (PCTO) has been prepared as polycrystalline powders by a solid state reaction route, and the crystal structure and magnetic properties have been investigated using a combination of X-ray and neutron powder diffraction, electron microscopy, dielectric, calorimetric and magnetic measurements. It was shown that at room temperature this compound adopts a trigonal perovskite structure, space group R (3) over bar (a = 5.6782(1) angstrom, c = 13.8552(3) angstrom). The compound undergoes a number of temperature-induced phase transitions and adopts four different structures in the temperature range 5 500 K: monoclinic in P2(1)/n (5 < T < 125 K, tilt system (a(+)b(-)b(-))), monoclinic in I2/m (125 < T < 210 K, tilt system (a(0)b(-)b(-))), rhombohedral in R (3) over bar (210 < T < 370 K, tilt system (a(-)a(-)a(-))), and finally cubic in Fm (3) over barm (above 370 K without any tilting). These structural phase transitions are coupled to changes in the dielectric constant and the heat capacity around 210 and 370 K. A long-range antiferromagnetically ordered state has been identified from neutron powder diffraction and magnetic studies at different temperatures. Magnetic diffraction peaks were registered below the transition at about 16 K and a possible model for the magnetic structure is proposed. Possible coexistence of long-range ordering of the electrical dipoles and the magnetic moments at low temperatures making PCTO a potential multiferroic candidate is discussed.
Place, publisher, year, edition, pages
2010. Vol. 39, no 46, 11136-11148 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:uu:diva-139275DOI: 10.1039/c0dt00558dISI: 000284314800006OAI: oai:DiVA.org:uu-139275DiVA: diva2:380894