First-order reversal curve (FORC) diagrams for pseudo-single-domain magnetites at high temperature

By A. Muxworthy, D. Dunlop. 2002

183 citations recorded by the source corpus.

Abstract The recently developed first-order reversal curve (FORC) technique for rapidly examining magnetic domain state has great potential for paleomagnetic and environmental magnetic investigations. However, there are still some gaps in the basic understanding of FORC diagrams, in particular the behavior of pseudo-single-domain (PSD) grains and the contribution of magnetostatic interactions. In this paper we address some of these problems. We report the first FORC diagrams measurements on narrowly sized and well-characterized synthetic PSD through multidomain (MD) magnetite samples. The FORC diagrams evolve with grain size from single-domain (SD)-like to MD-like through the PSD grain size range. Since each sample contains grains of essentially a single size, individual PSD grains evidently contain contributions from both SD-like and MD-like magnetic moments, in proportions that vary with grain size; the evolving FORC diagrams cannot be due to physical mixtures of SD and MD grains of widely different sizes. The FORC diagrams were all asymmetric. Small PSD samples have FORC diagrams with a distinctive closed-contour structure. The distributions of the larger MD grains display no peak, and lie closer to the interaction-field axis. To assess the effect of magnetostatic interactions, we measured FORC diagrams between room temperature and the Curie temperature. On heating the FORC distributions contract without changing shape until ∼500°C. Above this temperature the diagrams become more MD-like, and in addition become more symmetric. The temperature dependence of the interaction-field parameter is proportional to that of the saturation magnetization, in accordance with Neel’s interpretation of the Preisach diagram. The decrease in asymmetry with heating suggests that the origin of the asymmetry lies in magnetostatic interactions. The magnetic hysteresis parameters as a function of temperature were determined from the FORC curves. As the grain size decreased the normalized coercive force was found to decrease more rapidly with temperature.

Subfields: Electronic, Optical and Magnetic Materials, Geophysics, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/0e160b6842f350556d840a5af25f5dfdcc9a6390

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Electronic, Optical and Magnetic Materials

1. A. Roberts
2. D. Heslop
3. Andrew J. Newell
4. Xiang Zhao
5. R. Egli
6. Liao Chang
7. A. Muxworthy
8. C. R. Pike

In Geophysics

1. A. Roberts
2. D. Heslop
3. Xiang Zhao
4. R. Egli
5. Andrew J. Newell
6. C. R. Pike
7. Liao Chang
8. C. Horng

In Molecular Biology

1. A. Roberts
2. D. Heslop
3. Xiang Zhao
4. R. Egli
5. Andrew J. Newell
6. C. R. Pike
7. Liao Chang
8. J. Larrasoaña

Citations in the corpus

• Increasing the efficiency of paleointensity analyses by selection of samples using first-order reversal curve diagrams (2006, methodology): “By quantifying interaction field strengths using the parameters of Pike et al. [1999] and Muxworthy and Dunlop [2002] , it should be possible to empirically determine a threshold strength for interaction fields that would cause failure of the paleointensity experiment.”
• Searching for single domain magnetite in the “pseudo‐single‐domain” sedimentary haystack: Implications of biogenic magnetite preservation for sediment magnetism and relative paleointensity determinations (2012, background): “Low-resolution FORC diagrams reveal details of the terrigenous component, which has characteristics that are consistent with those of ‘PSD’ magnetite, particularly the asymmetrical distribution that diverges toward the Bb axis in the upper quadrant [Roberts et al., 2000; Muxworthy and Dunlop, 2002].”
• A high‐precision model of first‐order reversal curve (FORC) functions for single‐domain ferromagnets with uniaxial anisotropy (2005, methodology): “Suites of samples with varying ratios of components often follow trends on the Day plot [Parry, 1982; Jackson, 1990; Tauxe et al., 1996; Dunlop, 2002a, 2002b].”
• Resolving the Origin of Pseudo‐Single Domain Magnetic Behavior (2017, background): “In Figures 3c–3f, FORC diagrams are shown for magnetite with particle size from the MD through PSD size range from 76 to 7 μm (Muxworthy & Dunlop, 2002).”
• Detection of noninteracting single domain particles using first‐order reversal curve diagrams (2010, background): “FORC diagrams of pseudo– single domain (PSD) or multidomain (MD) particles have a large spread along Hu, and are roughly reflection symmetric about the Hc axis [Roberts et al., 2000; Pike et al., 2001b; Muxworthy and Dunlop, 2002].”
• Characterization of hematite (α-Fe2O3), goethite (α-FeOOH), greigite (Fe3S4), and pyrrhotite (Fe7S8) using first-order reversal curve diagrams (2006, methodology): “…al., 2002; Rowan and Roberts, 2006; Tarduno et al., 2006; Carvallo et al., 2006a], environmental magnetism [e.g., van Oorschot et al., 2002; Peck et al., 2004; Muxworthy et al., 2005] and rock magnetism [e.g., Muxworthy and Dunlop, 2002; Carvallo et al., 2003, 2004, 2006b; Muxworthy et al., 2004].”
• Understanding fine magnetic particle systems through use of first‐order reversal curve diagrams (2014, methodology): “…response of different magnetic minerals in FORC diagrams, we refer readers to the following key papers for magnetite [Roberts et al., 2000; Muxworthy and Dunlop, 2002], titanomagnetite [Carvallo et al., 2006a; Church et al., 2011], hematite [Muxworthy et al., 2005; Roberts et al., 2006;…”