Publikace na Přírodovědecká fakulta |
2014
Abstrakt
Monodisperse maghemite nanoparticles with diameter ranging from 7 to 20 nm were examined by the In-field Mossbauer Spectroscopy (IFMS) in varying external magnetic field up to 6 T. Surprisingly, the small-sized particles (7 nm) exhibit nearly no spin canting in contrast to the larger particles with lower surface-to-volume ratio.
We demonstrate that the observed phenomenon is originated by lower relative crystallinity of the larger particles with different internal structure. Hence, the persistence of the 2nd and 5th absorption lines in the IFMS cannot be unambiguously assigned to the surface spins.