Structural disorder versus spin canting in monodisperse maghemite nanocrystals

Journal Article · Mon Jun 02 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4881331· OSTI ID:22300088

Kubickova, S.; Niznansky, D. ^[1]; Morales Herrero, M. P. ^[2]; Salas, G. ^[2]

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1. Faculty of Science, Department of Inorganic Chemistry, Charles University in Prague, Albertov 2030, 128 40 Prague (Czech Republic)
2. Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Ins de la Cruz 3, Campus de Cantoblanco, 28049 Madrid (Spain)

Monodisperse maghemite nanoparticles with diameter ranging from 7 to 20 nm were examined by the In-field Mössbauer 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.

• OSTI ID: 22300088
• Journal Information: Applied Physics Letters, Vol. 104, Issue 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ABSORPTION
MAGNETIC FIELDS
MOESSBAUER EFFECT
NANOSTRUCTURES
SPECTROSCOPY
SPIN
SURFACES
NANOPARTICLES