We evaluate the energy barrier distributions of coupled Co particles as a function of their concentration, which changes the strength of magnetostatic interactions, in a multidimensional space to take into account possible collective reversal. The distributions are evaluated at the remanence, demagnetized state and coercivity for Co particles with 2D random anisotropy easy axes orientations and...

We report the thermal annealing-induced formation of ring-like structure of Zn(II)-doped magnetite from iron alkoxide leaf-like nanoplate precusor. The phase, structure and morphology of magnetite nanorings were comprehensively characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscope, scanning electron microscope, and transmission electron microscope....

[1] First-order reversal curve (FORC) diagrams have become a standard tool in rock magnetism, yet magnetite is the only magnetic mineral that is well characterized using FORC diagrams. We present FORC diagrams for predominantly single-domain (SD) synthetic aluminous hematite (a-Fe2-xAlxO3) and goethite (a-(FeAl)OOH) and natural greigite (Fe3S4) and pyrrhotite (Fe7S8) to constrain interpretation...

[1] Goethite (a-FeOOH) is an antiferromagnetic iron oxyhydroxide that forms as a weathering product of iron-bearing minerals. We systematically investigated the lowand room temperature properties of well-defined aluminous goethites [a-(Fe, Al)OOH] with varying grain size and Al content. A marked decrease in the Néel temperature with increasing Al content for goethite lowers the blocking tempera...

: Novel fluffy Fe@α-Fe2O3 core-shell nanowires have been synthesized using the chemical reaction of ferrous sulfate and sodium borohydride, as well as the post-annealing process in air. The coercivity of the as-synthesized nanowires is above 684 Oe in the temperature range of 5 to 300 K, which is significantly higher than that of the bulk Fe (approximately 0.9 Oe). Through the annealing process...

The filtered cathodic vacuum arc technique was employed to deposit magnetic films such as FeNi on silicon substrate. Using the normal cathode design, tetrahedral amorphous carbon and metals films can be deposited. If a magnetic target is used, the arc spot always preferably moves to the edge of the target and then extinguishes. Therefore, the arc is not stable and no film can be deposited. A ca...

This article presents magnetic data of a 300-m-thick Mio-Pliocene red clay and Quaternary loess-paleosol sequence near Chaona town in the Central Chinese Loess Plateau. Detailed magnetostratigraphy shows that the aeolian red clay began to accumulate at ca. 8.1 Ma. Here, we presented a high-resolution rock magnetic data at 20-40 cm intervals within 4.5-8 ka span per sample of this section, which...

In this study, the effects of various heat treatments on microstructure, mechanical and magnetic properties of HSLA-100 steel were evaluated. The heat treatments consisted of austenitizing at 900°C for 60 minutes, then quenching by different cooling rates via furnace, air, oil and water; and quenched specimens were aged at 600°C for one hour. Optical and field emission scanning electron m...

Am-Fe-N films have been made by dc magnetron sputtering and heating in-situ in nitrogen atmosphere. It is observed that the anisotropy changes from perpendicular to in-plane by nitrogenation. The Curie temperature is about 380 K. Aspects of structure, hysterisis loops, initial magnetization curves and temperature dependence of coercivity are discussed. SQUID magnetometer was used to measure the...