ISSN:
1432-0630
Keywords:
68.35
;
76.00
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract A Mössbauer spectroscopic study was performed on uniform spherical hematite particles (99±9 nm, Sample I) and those enriched with57Fe on the surface (Sample II). A striking difference was found between the spectra of these two samples, in that Sample I showed a spectrum with nearly symmetrical resonant absorption lines, while Sample II showed a spectrum with the lines broadened toward the central peaks asymmetrically. But after the57Fe-enriched sample was heated to 623 K, the spectral lines became narrower due to the diffusion of the surface57Fe-ions into the bulk. The above results showed that the centripetal broadening of the spectral lines for small uniform hematite particles resulted from a surface effect. The surface exhibited a hyperfine field about 5.2% lower than that for the bulk. The wider distribution of the surface hyperfine field was explained by structural inhomogeneity of the surface.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00615011
