Observing thermomagnetic stability of nonideal magnetite particles: Good paleomagnetic recorders?. Issue 20 (18th October 2014)

• Record Type: Journal Article
• Authors: Almeida, Trevor P.; Kasama, Takeshi; Muxworthy, Adrian R.; Williams, Wyn; Nagy, Lesleis; Dunin‐Borkowski, Rafal E.
• Is Part Of: Geophysical research letters. Volume 41:Issue 20(2014:Oct.)
• Page Start: 7041
• Page End: 7047
• Publication Date: 2014-10-18
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2014GL061432
• Languages: English
• ISSNs: 0094-8276

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>The thermomagnetic behavior of remanence‐induced magnetite (Fe₃O₄) particles in the pseudo‐single‐domain (PSD) size range (~0.1–10 µm), which dominate the magnetic signature of many rock lithologies, is investigated using off‐axis electron holography. Construction of magnetic induction maps allowed for the visualization of the vortex domain state in an individual Fe₃O₄ grain (~200 nm in diameter) as a function of temperature. Acquisition of a series of electron holograms at 100°C intervals during in situ heating up to 700°C demonstrates the vortex state of the Fe₃O₄ grain, in this instance, remains thermally stable close to its unblocking temperature and exhibits a similar in‐plane remanent state upon cooling; i.e., the particle is effectively behaving like a uniaxial single‐domain particle to temperatures near <italic>T_C</italic>. Such particles are thought to be robust magnetic recorders. It is suggested that evidence for PSD behavior should therefore not preclude paleomagnetic investigation.</p> </abstract>