The Role of Magnetostatic Interactions on the Anisotropy of Magnetic Remanence: Micromagnetic Modeling of Distribution Anisotropy. <p> HR: <span class="hr"> 08:00h<br></span> AN: <span class="an"> GP31A-01 INVITED <a href="../absbook/fm03-GP31A.pdf">[PDF]</a><br></span> TI: <span class="ti"> The Role of Magnetostatic Interactions on the Anisotropy of Magnetic Remanence: Micromagnetic Modeling of Distribution Anisotropy. <br></span> AU: <span class="au"> * Muxworthy, A R<br></span> EM: <span class="em"> adrian.muxworthy@ed.ac.uk<br></span> AF: <span class="af"> Edinburgh University, Institute of Earth Sciences, Kings Buildings, West Mains Road, Edinburgh, EH9 3JW United Kingdom <br></span> AU: <span class="au"> Williams, W <br></span> EM: <span class="em"> wyn.williams@ed.ac.uk<br></span> AF: <span class="af"> Edinburgh University, Institute of Earth Sciences, Kings Buildings, West Mains Road, Edinburgh, EH9 3JW United Kingdom <br></span> AB: <span class="ab"> The anisotropy of magnetic remanence (AMR) is often used as a tool for examining magnetic anisotropy of rocks. However, the influence of magnetostatic interactions on AMR has not been rigorously addressed either theoretically or experimentally, though it is widely thought to be highly significant. Theoretically the problem has not been previously tackled due to the difficulty in solving the non-linear magnetostatic interaction field; it is computationally intensive. While experimentally, the problem has been avoided because of the difficulty in accurately synthesizing grains with controlled interaction spacings. Using a three-dimensional micromagnetic model we have conducted a systematic study of the role of magnetostatic interactions on AMR. We have considered both lineation and foliation, by modeling assemblages of ideal single domain grains and magnetically non-uniform magnetite-like cubic grains between 30-150 nm in size. In addition to varying grain size, we have also considered both uniaxial and cubic anisotropy. We show that magnetostatic interactions strongly affect the measured AMR signal. We have used a different micromagnetic model to those previously reported by the Edinburgh group; it is a combination model. As a first-step it determines the magnetic structure by a Fast-Fourier-transform conjugate gradient energy minimization. This solution is then refined using a dynamic solution of the Landau-Lifshitz-Gilbert equation. <br></span> DE: <span class="de"> 1518 Magnetic fabrics and anisotropy<br></span> DE: <span class="de"> 1540 Rock and mineral magnetism<br></span> DE: <span class="de"> 3210 Modeling<br></span> DE: <span class="de"> 3230 Numerical solutions<br></span> DE: <span class="de"> 5109 Magnetic and electrical properties<br></span> SC: <span class="sc"> Geomagnetism and Paleomagnetism [GP]<br></span> MN: <span class="mn"> 2003 Fall Meeting<br></span></p></body></html>