TY  - JOUR
AU  - Zákutná, Dominika
AU  - Nižňanský, Daniel
AU  - Barnsley, Lester C.
AU  - Babcock, Earl
AU  - Salhi, Zahir
AU  - Feoktystov, Artem
AU  - Honecker, Dirk
AU  - Disch, Sabrina
TI  - Field Dependence of Magnetic Disorder in Nanoparticles
JO  - Physical review / X Expanding access
VL  - 10
IS  - 3
SN  - 2160-3308
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2020-02650
SP  - 031019
PY  - 2020
AB  - The performance characteristics of magnetic nanoparticles toward application, e.g., in medicine and imaging or as sensors, are directly determined by their magnetization relaxation and total magnetic moment. In the commonly assumed picture, nanoparticles have a constant overall magnetic moment originating from the magnetization of the single-domain particle core surrounded by a surface region hosting spin disorder. In contrast, this work demonstrates the significant increase of the magnetic moment of ferrite nanoparticles with an applied magnetic field. At low magnetic field, the homogeneously magnetized particle core initially coincides in size with the structurally coherent grain of 12.8(2) nm diameter, indicating a strong coupling between magnetic and structural disorder. Applied magnetic fields gradually polarize the uncorrelated, disordered surface spins, resulting in a magnetic volume more than 20% larger than the structurally coherent core. The intraparticle magnetic disorder energy increases sharply toward the defect-rich surface as established by the field dependence of the magnetization distribution. In consequence, these findings illustrate how the nanoparticle magnetization overcomes structural surface disorder. This new concept of intraparticle magnetization is deployable to other magnetic nanoparticle systems, where the in-depth knowledge of spin disorder and associated magnetic anisotropies are decisive for a rational nanomaterials design.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000552226600001
DO  - DOI:10.1103/PhysRevX.10.031019
UR  - https://juser.fz-juelich.de/record/878132
ER  -