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The phenomenon of exchange bias has been extensively studied within crystalline materials, encompassing a broad spectrum from nanoparticles to thin-film systems. Nonetheless, exchange bias in amorphous alloys has remained a relatively unexplored domain, primarily owing to their inherently uniform disordered atomic structure and lacking grain boundaries. In this study, we present a unique instance of exchange bias observed in Fe–B–Nb amorphous thin films, offering insights into its origins intertwined with the system's spin-glass-like behavior at lower temperatures. The quantification of exchange bias was accomplished through a meticulous analysis of magnetic reversal behaviors in the liquid-helium temperature range, employing a zero-field cooling approach from various initial remanent magnetization states (±MR). At reduced temperatures, the appearance of asymmetric hysteresis, a hallmark of negative exchange bias, undergoes a transformation into symmetric hysteresis loops at elevated temperatures, underscoring the intimate connection between exchange-bias and dynamic magnetic states. Further investigations into the magnetic thermal evolution under varying probe fields reveal the system's transition into a spin-glass-like state at low temperatures. We attribute the origin of this unconventional exchange bias to the intricate exchange interactions within the spin-glass-like regions that manifest at the interfaces among highly disordered Fe-nuclei. The formation of Fe-nuclei agglomerates at the sub-nanometer scale is attributed to the alloy's limited glass-forming ability and the nature of the thin-film fabrication process. We propose that this distinctive form of exchange bias represents a novel characteristic of amorphous thin films. [ABSTRACT FROM AUTHOR]

The kinetics of the nanocrystallization of a Fe83.3Si4B8P4Cu0.7 amorphous alloy by using differential scanning calorimetry has been investigated by non-isothermal annealing in a wide heating rate range from 10 °C min−1 to 200 °C min−1. The amorphous alloy was prepared by melt-spinning and showed a two-stage crystallization. In the first crystallization stage, α-Fe nanocrystals are formed. This phase is responsible for the good soft magnetic properties. The activation energy during the crystallization of the α-Fe nanocrystalline phase was determined from an isoconversional approach, and was found to be distinctively varying during the crystallization. An attempt was made to model the crystallization in an interval where the activation energy is relatively constant. The Malek criterion indicated that the Kolmogorov–Johnson–Mehl–Avrami model is not appropriate, whereas the Sestak–Berggren model meets the criterion. The acquired model shows good agreement with the experimental results. The magnetic properties of annealed ribbons at different heating rates show an initially steep decrease of the coercivity (Hc) from 82 A m−1 at a heating rate of 10 °C min−1 to 20 A m−1 above 100 °C min−1, whereas saturation magnetization (Ms) is practically invariant at ca 175 Am2 kg−1. This dependence is explained as due to diminishing grain size with higher heating rates, which is further supported by x-ray diffraction measurements. [ABSTRACT FROM AUTHOR]

We present a study of the influence of substrate roughness on the magnetic properties of thin fcc Co films (7 and 17 nm thick) grown on Cu(001)/Si(001). A significant decrease in cubic anisotropy with increasing film roughness was observed with Brillouin light scattering. In addition, the rougher samples exhibited a substantial broadening of the spin wave peaks. Both effects were found to be more pronounced for the thinner Co layers. We propose a magnetic configuration with the magnetization following coherently the substrate morphology (“undulating” state) resulting in the absence of magnetic surface charges. This configuration gives rise to a reduction in the magnetic anisotropy of epitaxial thin films, in good qualitative agreement with the experimental observations. [ABSTRACT FROM AUTHOR]

Provides information on a study which investigated the effect of cooling rate, followed immediately after the isothermal annealing, on the magnetic properties of a melt-spun iron compound alloy. Methods; Results; Discussion.

Deals with a study which described the magnetic properties of iron and iron oxide nanoparticles produced by pulsed laser evaporation in different oxygen partial pressure atmosphere. Methods; Results; Discussion.

Presents a study which focused on the superconducting properties of mercury-1223 prepared by using fluorides. Methods; Results and discussion; Conclusion.

Abstract Background The present study sought to determine if subjects who had consumed coffee before performing a simulated computer office-work task found to provoke pain in the neck and shoulders and forearms and wrists exhibited different time course in the pain development than the subjects who had abstained from coffee intake. Findings Forty eight subjects all working fulltime, 22 with chronic shoulder and neck pain and 26 healthy pain-free subjects, were recruited to perform a computer-based office-work task for 90 min. Nineteen (40%) of the subjects had consumed coffee (1/2 -1 cup) on average 1 h 18 min before start. Pain intensity in the shoulders and neck and forearms and wrists was rated on a visual analogue scale every 15 min throughout the work task. During the work task the coffee consumers exhibited significantly lower pain increase than those who abstained from coffee. Conclusions Subjects who had consumed coffee before starting a pain provoking office work task exhibited attenuated pain development compared with the subjects who had abstained from coffee intake. These results might have potentially interesting implications of a pain-modulating effect of caffeine in an everyday setting. However, studies with a double blind placebo controlled randomized design are needed.