The demagnetization of a hard ferromagnetic layer via the fringing fields of domain walls created by reversing the moment of a neighboring soft ferromagnetic layer is explored experimentally. An unusual oscillatory decay of the magnetic moment of the hard layer is observed using structures in which the demagnetization occurs after a few hundred cycles. This surprising observation is confirmed o...

We introduce a method and software to process demagnetization data for a rapid and integrative estimation of characteristic remanentmagnetization (ChRM) components. The virtual directions (VIDI) of a paleomagnetic site are “all” possible directions that can be calculated from a given demagnetization routine of “n” steps (being m the number of specimens in the site). If the ChRM can be defined f...

The magnetic remanence of silica microspheres with a low concentration of embedded cobalt ferrite nanoparticles is studied after demagnetization and remagnetization treatments. When the microspheres are dispersed in a liquid, alternating current (AC) magnetic susceptibility spectra reveal a constant characteristic frequency, corresponding to the rotational diffusion of the microparticles; this ...

Femtosecond magnetization phenomena have been challenging our understanding for over a decade. Most experiments have relied on infrared femtosecond lasers, limiting the spatial resolution to a few micrometres. With the advent of femtosecond X-ray sources, nanometric resolution can now be reached, which matches key length scales in femtomagnetism such as the travelling length of excited 'hot' el...

Battiato, M. 2013. Superdiffusive Spin Transport and Ultrafast Magnetization Dynamics: Femtosecond spin transport as the route to ultrafast spintronics. Acta Universitatis Upsaliensis. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1061. 62 pp. Uppsala. ISBN 978-91-554-8722-5. The debate over the origin of the ultrafast demagnetization has be...

To demagnetize small-scale objects (dimensions less than 1 m) fabricated from ferromagnetic materials, it is standard practice to expose the object to a continuous ac applied magnetic field with a steadily decaying amplitude. For objects of dimensions greater than 10 m, there are problems of scale, and a stepwise procedure is preferred. We have simulated two different stepwise demagnetization t...

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 (~250 nm in diameter) during in situ heating is achieved through the construction and examination of magnetic-induction maps. Stepwis...

In this paper, the effect of alloy composition on the microstructural development of devitrified Nd–Fe–B-based alloys is investigated. While crystallization of simple ternary Nd2Fe14B resulted in a highly variable microstructure and relatively poor demagnetization behavior, alloying additions, notably Ti and C, were found to significantly refine and homogenize the crystallized microstructure. H...

The note describes measurement of NdFeB permanent magnet (PM) material demagnetization induced by high-energy electron radiation. In experiments we compared N40 and N40SH grades from Stanford Magnets Company, which have different intrinsic coercive forces. Dimensions of the tested PM blocks were close to those that will be used for ERL undulator construction. It was found that depending on dire...