TY - JOUR
T1 - Direct observation of the thermal demagnetization of magnetic vortex structures in nonideal magnetite recorders
T2 - Thermal Demagnetization of Vortex States
AU - Almeida, Trevor P.
AU - Muxworthy, Adrian R.
AU - Kovács, András
AU - Williams, Wyn
AU - Nagy, Leslei
AU - Conbhuí, Pádraig O.
AU - Frandsen, Cathrine
AU - Supakulopas, Radchagrit
AU - Dunin-Borkowski, Rafal E.
N1 - This is an open access article under the terms of the Creative Commons Attribution License
PY - 2016
Y1 - 2016
N2 - 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 (~250nm 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.
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 (~250nm 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.
U2 - 10.1002/2016GL070074
DO - 10.1002/2016GL070074
M3 - Journal article
C2 - 27867236
SN - 0094-8276
VL - 43
SP - 8426
EP - 8434
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 16
ER -