Direct observation of a surface induced disordering process in magnetic nanoparticles.
We present experimental evidence of surface induced disordering at magnetic FeCoPd nanoparticles during the L1(0)-A1 phase transition using high-resolution aberration-corrected electron microscopy and strain mapping. In situ electron diffraction studies show a narrow temperature range of fully ordered L1(0) structure. The order-disorder transition is size dependent and induces strong lattice deformation in outer part of the nanocrystals. The formation of unusually large strain of 20% is discussed in terms of core-shell structure formation with surface disordered layer and ordered core.
Kovács
András
A
Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford, United Kingdom. andras.kovacs@materials.ox.ac.uk
Sato
Kazuhisa
K
Lazarov
Vlado K
VK
Galindo
Pedro L
PL
Konno
Toyohiko J
TJ
Hirotsu
Yoshihiko
Y