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Representing components combined in series or parallel as a single equivalent component is a powerful tool for simplifying systems, both in mechanics and in electrical circuits. When combining inductors, the effect of mutual inductance decreases or increases the total inductance of the system, depending on the coupling factor between the inductors and on how they are connected. The analysis of mutually coupled inductors can be complex and is often avoided, obscuring the underlying physics. Here, we discuss the dependence of the equivalent inductance on the coupling factor for two parallel-connected inductors with linear magnetic core and negligible resistance. By analyzing the current distribution in each coil, we show that the so-called aiding and opposing arrangements are more complicated than is frequently assumed. We recommend avoiding these terms and calling them instead aligned and anti-aligned arrangements. [ABSTRACT FROM AUTHOR]

Electrical steels are still the materials of choice for large-scale transformers and most electric motors. Yet, they may present a nonhomogeneous magnetic nature which prevents describing accurately their anhysteretic magnetization with the Langevin-Weiss model. Although interpolation and extrapolation methods may be used to model any anhysteretic curve, a simple and physically-based model would be of great value for fundamental and applied research. Inspired in the law of partial volumes for gas mixtures, we proposed a law of partial magnetizations for magnetic mixtures. In a two-component system, the model leads to the double Langevin-Weiss function. We also introduced a graphical method and a fitting approach to analyze and model anhysteretic magnetization curves. A semi-log magnetization derivative plot is central to this end. We validated our strategy through well-motivated examples using published data on soft magnets. The single Langevin-Weiss function provided an accurate description of the magnetization of isotropic and anisotropic magnetically homogeneous materials: a soft ferrite and a nanocrystalline alloy, respectively. For modelling a magnetization transverse to the material's preferred direction, the key is to allow a negative molecular field constant. The double Langevin-Weiss function was suitable for less homogeneous materials, such as a grain-oriented electrical steel magnetized along the rolling direction and a non-oriented electrical steel. Moreover, a highly-grain-oriented electrical steel magnetized transverse to the rolling direction, which exhibits a constricted hysteresis loop, could be modeled in excellent agreement with data. The key for the latter, has been to allow an antiparallel arrangement of the mean magnetization of both components. [ABSTRACT FROM AUTHOR]

The pulsed laser ablation process is a widely used technique for thin films deposition. In this method, a pulsed laser beam focuses onto a target ablating the impact site, called spot. Since preparing the target is a highly time consuming and expensive task, the spot is generally scanned across the target's surface. A typical pulsed laser deposition configuration has a moving mirror that scans the laser beam across a rotating target. We propose ablating the target with a spiral pattern to ensure a uniform ablation and maximizing the target's efficiency. This requires moving the mirror and target in sync with variable speeds. To this end, we designed and built robust electromechanical actuators driven by stepper motors, which are electronically controlled by an Arduino-based system. The core of the firmware is a precalculated lookup table with the time intervals between the motors' steps. Thus, motor control following computationally expensive positioning functions -as the spiral pattern- are not a problem. Users may operate the control system through a user-friendly interface. The modular firmware architecture facilitates future extensions as, for example, adding other motor positioning functions to enable different ablation patterns for research purposes. This development aims to be a valuable tool for the synthesis of thin films by pulsed laser deposition. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the phase transformations occurring during the crystallization process of FINEMETs in which Nb has been gradually replaced by Mo have been studied by a variety of techniques including DSC, DTA, TGA, XRD and TEM. The thermal stability of the alloy was deteriorated as a consequence of Mo’s smaller atomic size. The gradual replacement of Nb by Mo reduced the onset temperature of Fe–Si and of the borides. The Curie temperature of the amorphous phase slightly decreased from 594K for x=0 to 587K for x=3. The borides compounds Fe2B and Fe23B6 as well as the (Nb,Mo)5Si3 phase were found to precipitate in the second and third crystallization. [Copyright &y& Elsevier]

FINEMET type ribbons (Fe73.5Si13.5Nb3 − xMoxB9Cu1, x = 1.5, 2 at.%) were produced by the planar flow casting technique and subsequently heat treated at 823 K to induce nanocrystallization and to optimize its soft magnetic properties. The coercivity, measured by conventional fluxmetric method, resulted in HC = 0.53 ±0.10 and 0.41±0.05 A/m for x = 1.5 and 2 respectively. A correlation between magnetic properties and the amorphous and nanocrystalline phases when Nb was partially substituted with Mo was studied by means of Mössbauer spectroscopy and X-ray diffraction. [ABSTRACT FROM AUTHOR]

Abstract: The structure and the dc magnetic behavior of FINEMET-type alloys doped with molybdenum have been recently reported. Most commercial applications of these materials are, however, not at dc but at high magnetizing frequencies. Therefore, we report a study of the frequency dependence of coercivity, H c (f), in amorphous and nanocrystalline ribbons of composition Fe73.5Si13.5Nb3−x Mo x B9Cu1 (x=0, 1.5 and 3) in the frequency range from 0.5 to 1.3kHz. The nature of H c (f) measurements revealed the influence of eddy currents in the magnetization of samples. The frequency dependence of coercivity did not vary with the molybdenum content in the amorphous samples. All the alloys exhibited a systematic improvement in the coercivity after nanocrystallization and it was found that this improvement was better as more Nb was replaced by Mo. [Copyright &y& Elsevier]