Premium
Suppression of the Verwey Transition by Charge Trapping
Author(s) -
SchmitzAntoniak Carolin,
Schmitz Detlef,
Warland Anne,
Darbandi Masih,
Haldar Soumyajyoti,
Bhandary Sumanta,
Sanyal Biplab,
Eriksson Olle,
Wende Heiko
Publication year - 2018
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.201700363
Subject(s) - charge ordering , trapping , magnetic circular dichroism , materials science , ion , absorption spectroscopy , condensed matter physics , magnetization , spectroscopy , charge (physics) , absorption (acoustics) , lattice (music) , spectral line , magnetic field , chemistry , physics , optics , ecology , organic chemistry , quantum mechanics , astronomy , acoustics , composite material , biology
The Verwey transition in Fe 3 O 4 nanoparticles with a mean diameter of 6.3 nm is suppressed after capping the particles with a 3.5 nm thick shell of SiO 2 . By X‐ray absorption spectroscopy and its associated X‐ray magnetic circular dichroism this suppression can be correlated to localized Fe 2+ states and a reduced double exchange visible in different site‐specific magnetization behavior in high magnetic fields. The results are discussed in terms of charge trapping at defects in the Fe 3 O 4 / SiO 2 interface and the consequent difficulties in the formation of the common phases of Fe 3 O 4 . By comparison to X‐ray absorption spectra of bare Fe 3 O 4 nanoparticles in course of the Verwey transition, particular changes in the spectral shape could be correlated to changes in the number of unoccupied d states for Fe ions at different lattice sites. These findings are supported by density functional theory calculations.