The influence of halogen compounds on gaseous oxidation processes

Imperial Users onl

Crystallographic and magnetic identification of secondary phase in orientated Bi5Fe0.5Co0.5Ti3O15 ceramics

Oxide materials which exhibit both ferroelectricity and ferromagnetism are of great interest for sensors and memory applications. Layered bismuth titanates with an Aurivillius structure, (BiFeO3)nBi4Ti3O12, can possess ferroelectric and ferromagnetic order parameters simultaneously. It has recently been demonstrated that one such example, Bi5Fe0.5Co0.5Ti3O15,where n = 1 with half the Fe3+ sites substituted by Co3+ ions, exhibits both ferroelectric and ferromagnetic properties at room temperature. Here we report the fabrication of highly-oriented polycrystalline ceramics of this material, prepared via molten salt synthesis and uniaxial pressing of high aspect ratio platelets. Electron backscatter images showed that there is a secondary phase within the ceramic matrix which is rich in cobalt and iron, hence this secondary phase could contribute in the main phase ferromagnetic property. The concentration of the secondary phase obtained from secondary electron microscopy is estimated at less than 2.5 %, below the detection limit of XRD. TEM was used to identify the crystallographic structure of the secondary phase, which was shown to be cobalt ferrite, CoFe2O4. It is inferred from the data that the resultant ferromagnetic response identified using VSM measurements was due to the presence of the minor secondary phase. The Remanent magnetization at room temperature was Mr ≈ 76 memu/g which dropped down to almost zero (Mr ≈ 0.8 memu/g) at 460 oC, far lower than the anticipated for CoFe2O4

Evidence of a large seasonal coastal upwelling system along the southern shelf of Australia

2000 FLORIDA AVE NW, WASHINGTON, USA, DC, 2000

Conversion in American Philosophy

In this fresh, provocative account of the American philosophical tradition, Roger Ward explores the work of key thinkers through an innovative and counterintuitive lens: religious conversion. From Jonathan Edwards to Cornel West, Ward threads the history of American thought into an extended, multivalent encounter with the religious experience. Looking at Dewey, James, Peirce, Rorty, Corrington, and other thinkers, Ward demonstrates that religious themes have deeply influenced the development of American philosophy.This innovative reading of the American philosophical tradition will be welcomed not only by philosophers, but also by historians and other students of America's religious, intellectual, and cultural legacy