TY  - JOUR
AU  - Almeida, T. P.
AU  - Muxworthy, A. R.
AU  - Kovacs, Andras
AU  - Williams, W.
AU  - Nagy, L.
AU  - Conbhuí, P.Ò
AU  - Frandsen, C.
AU  - Supakulopas, R.
AU  - Dunin-Borkowski, Rafal
TI  - Direct observation of the thermal demagnetization of a vortex structure held by a non-ideal magnetite recorder
JO  - Geophysical research letters
VL  - 43
IS  - 16
SN  - 0094-8276
CY  - Hoboken, NJ
PB  - Wiley
M1  - FZJ-2017-01265
SP  - 8426 - 8434
PY  - 2016
AB  - The thermal demagnetization of pseudo-single-domain (PSD) magnetite (Fe3O4) particles, which govern the magnetic signal in many igneous rocks, is examined using off-axis electron holography. Visualization of a vortex structure held by an individual Fe3O4 particle (~250 nm in diameter) during in situ heating is achieved through the construction and examination of magnetic-induction maps. Stepwise demagnetization of the remanence-induced Fe3O4 particle upon heating to above the Curie temperature, performed in a similar fashion to bulk thermal demagnetization measurements, revealed that its vortex state remains stable under heating close to its unblocking temperature and is recovered upon cooling with the same or reversed vorticity. Hence, the PSD Fe3O4 particle exhibits thermomagnetic behavior comparable to a single-domain carrier, and thus, vortex states are considered reliable magnetic recorders for paleomagnetic investigations
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000384443800012
C6  - pmid:27867236
DO  - DOI:10.1002/2016GL070074
UR  - https://juser.fz-juelich.de/record/827059
ER  -