Year: 2014
Type: article
Abstract: Mössbauer spectra of 151 Eu in 20 nm nanoparticles of EuS were measured at several temperatures. The samples were found to contain up to 30% of Eu 3+ , which suggests that surface oxidation of the nanostructures penetrated farther than the ∼12% of atomic sites on the outermost surface of the nanoparticles. Below the Curie temperature, T c = 16.6 K, the spectra showed line broadening due to superparamagnetic fluctuations with an average Mössbauer blocking temperature of about 16 K. Below 10 K, the spectrum became a fully split magnetic hyperfine pattern with an effective field of 29.9 T at 5 K. The spectra were compared with those of bulk ferromagnetic EuS. This approach provides considerable information about the composition of oxygen-sensitive nanoscale materials.
Institutions: Northern Illinois University, Vanderbilt University
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1978553993