ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Single-phase nickel manganite spinels, Ni x Mn3−x O4, with 0.5 ⩽x ⩽ 1, were prepared by a careful thermal processing of nickel-manganese coprecipitated oxalate precursors. Powder X-ray diffraction analysis of the spinel revealed the presence of cubic single spinel phase with parametera which decreases with nickel content. The lattice parameter variation can be explained in terms of the distribution of Ni2+ ions on the octahedral sites. Therefore, a fine analysis of data shows that some Ni2+ ions (forx〉0.56) are located in tetrahedral sites. The percentage of nickel in A-sites increases with nickel content (x) following the relation % Ni2+ in A sites =P = − 82.1x 2+192.4x−81.5 and thus the general formula for cation distribution is $${\text{Mn}}_{{\text{1 - }}y}^{{\text{2 + }}} {\text{Ni}}_y^{{\text{2 + }}} [{\text{Ni}}_{x{\text{ - }}y}^{{\text{2 + }}} {\text{Mn}}_{{\text{2 - 2(}}x - y)}^{{\text{3 + }}} {\text{Mn}}_{x{\text{ - }}y}^{{\text{4 + }}} ]{\text{O}}_{\text{4}}^{{\text{2 - }}} $$ withy=xP/100 This relationship explains the electrical properties of semiconducting nickel manganite ceramics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00581101
