An experimental study of the intensity and stability of thermoremanent magnetization acquired by synthetic monodomain titanomagnetite substituted by aluminium |
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Authors: | Ö Özdemir W O'Reilly |
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Institution: | Department of Geophysics and Planetary Physics, School of Physics, University of Newcastle upon Tyne, Newcastle upon Tyne NEl 7RU |
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Abstract: | Summary. Titanomagnetites of composition Fe2.4-δAlδTi0.6O4 and Fe2.6-δAlδTi0–4O4(δ=0, 0.1 and 0.2 in both cases) were prepared in the monodomain state by pulverization of sintered synthetic material. In low fields, the thermoremanence (TRM) was found to be linear with inducing field and of high enough intensity to account for typical natural remanent magnetizations of fresh submarine basalts. The higher field TRM acquisition curves follow the Néel model curve for an assemblage of non-interacting identical particles in a general way only, the differences being due to interactions, or the range of particle blocking temperatures and volumes or other features of the samples not included in the model. The unblocking temperatures of low field TRM lie in a narrow range below the Curie point. The low field TRM is very resistant to alternating field demagnetization and provides a very striking illustration of the strength of the TRM mechanism in preserving a stable record of a weak magnetic field. The result of a Lowrie-Fuller test on the material is consistent with the monodomain state. |
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