Thin film deposition of arsenic free pnictide superconductors

The aim of this work is the thin film deposition of arsenic free pnictide superconductor by reactive molecular beam epitaxy (r-MBE). Starting from the so-called '1111'-phase, it is attempted to deposit LaNiBiO1-x on MgO substrates. The deposited polycrystalline films are characterized by X-ray diffraction and four-point resistivity measurement, phase pure, single crystal layers are, however, not realized due to the required oxidation conditions. Therefore, the focus is placed on oxygen-free layers and it is a so-called '122'-phase, La1-xNi2Bi2 deposited. During the process parameters optimization of this phase, the so-called '112'-phase, LaNi1 XBi2, is discovered. The procedure of the process parameters optimization for the deposition of the new pahse is described in detail. The single-crystal, epitaxial layers are analyzed using X-ray diffractometer, four-point resistivity measurement and SQUID magnetometer. The layers are superconducting below 4K. The influence of the Ni and the Bi content is examined. In addition the La is substituted by Ce, which results in an increase of superconducting transition temperature. Here, too, the influence of the Ni and Bi content is examined

Thin film deposition of arsenic free pnictide superconductors

The aim of this work is the thin film deposition of arsenic free pnictide superconductor by reactive molecular beam epitaxy (r-MBE). Starting from the so-called '1111'-phase, it is attempted to deposit LaNiBiO1-x on MgO substrates. The deposited polycrystalline films are characterized by X-ray diffraction and four-point resistivity measurement, phase pure, single crystal layers are, however, not realized due to the required oxidation conditions. Therefore, the focus is placed on oxygen-free layers and it is a so-called '122'-phase, La1-xNi2Bi2 deposited. During the process parameters optimization of this phase, the so-called '112'-phase, LaNi1 XBi2, is discovered. The procedure of the process parameters optimization for the deposition of the new pahse is described in detail. The single-crystal, epitaxial layers are analyzed using X-ray diffractometer, four-point resistivity measurement and SQUID magnetometer. The layers are superconducting below 4K. The influence of the Ni and the Bi content is examined. In addition the La is substituted by Ce, which results in an increase of superconducting transition temperature. Here, too, the influence of the Ni and Bi content is examined

Superconducting epitaxial thin films of CeNi[sub x]Bi[sub 2] with a bismuth square net structure

We have grown highly epitaxial and phase pure thin films of the arsenic-free pnictidecompoundCeNixBi2 on (100) MgO substrates by reactive molecular beam epitaxy (RMBE). X-ray diffraction and reflection high-energy electron diffraction of the films confirm the ZrCuSiAs structure with a Bi square net layer. Superconductivity was observed in magnetization and resistivity measurements for x = 0.75 to 0.93 in these CeNixBi2thin films with the highest critical temperature of 4.05 K and a resistive transition width of 0.1 K for x = 0.86. Our results indicate that thin film deposition by RMBE provides a tool to synthesize high-quality pnictidesuperconductors of the novel 112 type

Seltene Erden - Seltenerdhaltige Permanentmagnete effizient recyceln

Viele moderne Technologien basieren auf dem Einsatz funktionaler Materialien, die aufgrund ihrer chemischen Zusammensetzung und ihrer Mikrostruktur für die jeweiligen Anwendungen spezielle makroskopische Eigenschaften aufweisen

Verfahren zum Recycling von Permanentmagneten durch Schmelzen und Rascherstarren

The invention relates to a recycling method for producing powders containing magnetic alloys, having the following steps: a) providing a magnetic alloy from scrap magnetic material comprising a1) at least one rare-earth metal, a2) at least one transition metal, and a3) boron; b) mixing and melting the alloys provided in steps a) and b); c) quickly solidifying the molten metal from step b) under an inert gas atmosphere, thereby forming platelets, and d) grinding the platelets obtained in step d) into a powder, wherein prior to or during step b), a magnetic alloy of a primary magnetic material comprising the components a1) to a3) is added and melted together with the alloy provided in step a), or after step d), a magnetic alloy of the primary magnetic material comprising the components a1) to a3) is added and the content of the alloy of the primary magnetic material equals 5 to 95 wt.%, based on the weight of the alloy provided in step a). The invention additionally relates to a powder which can be produced using the method according to the invention and to the applications thereof

Efficient recycling of rare earth permanent magnets: Applications and present situation

Many advanced technologies are based on the use of functional materials. Due to their chemical composition and microstructure these materials offer certain macroscopic properties useful for their specific applications. Modern vehicles contain a large number of electronic micromotors, electric actuators and powertrains are widely used also in the mechanical engineering industry. Audio devices and hard disks have become an integral part of the private as well as of the business life. For the future more and more energy will be produced via wind power and electric mobility will replace present mobility technologies, which are based on fossil fuels [1]

Superconductivity and role of pnictogen and Fe substitution in 112-LaPdxPn2(Pn=Sb,Bi)

We report on the epitaxial growth of As-free and phase-pure thin films of the 112-pnictide compounds LaPdxPn2 (Pn=Sb,Bi) grown on (100) MgO substrates by molecular beam epitaxy. X-ray diffraction, reflection high-energy electron diffraction, and x-ray photoelectron spectroscopy confirm the HfCuSi2 structure of the material with a peculiar pnictogen square net layer. The superconducting transition temperature Tc varies little with Pd concentration. LaPdxSb2 has a higher Tc (3.2 K) by about 20% compared with LaPdxBi2 (2.7 K). Fe substitution of Pd leads to a rapid decay of superconductivity, suggesting that these superconductors are conventional type II

Towards an Alloy Recycling of Nd–Fe–B Permanent Magnets in a Circular Economy

Rare earth permanent magnets are an integral part of many electrical and electronic devices as well as numerous other applications, including emerging technologies like wind power, electric vehicles, fully automized industrial machines, and robots. Due to their outstanding properties, magnets based on Nd–Fe–B alloys are often not substitutable by employing less critical material systems. Today, WEEE (Waste Electrical and Electronic Equipment) take-back systems for a variety of products containing Nd–Fe–B magnets are well established. They form an ideal basis for a systematic provision of scrap magnets that can be recycled. Hydrometallurgical approaches that aim at completely dissolving the material to regain elements or oxides are energy and time consuming. Thus, they are costly and come with a large environmental footprint. Recycled rare earth elements and oxides would have to compete with virgin materials from China and can hardly be processed in Europe, due to the lack of respective industries. This paper presents material-to-material recycling approaches, which would maintain the magnet alloys and use them directly for a new magnet production loop. The recycled magnets compete well with those made from primary materials, that is, in terms of magnetic properties as well as in terms of production costs. They excel by far rare earth permanent magnets made from primary materials regarding the environmental footprint. Regarding the shift towards a Green Economy, humanity will consume less fuels in combustion processes but rather exploit functional materials in renewable energy and mobility technologies in the future. This shift fundamentally depends on a circular economy of noble as well as less-noble technology metals

Recyclingverfahren zur Herstellung isotroper, magnetischer Pulver

Die vorliegende Erfindung betrifft Recyclingverfahren zur Herstellung von isotropen, magnetischen Pulvern umfassend die Schritte: a) Bereitstellen einer magnetischen Legierung umfassend a1) zumindest ein Seltenerdmetall, a2) zumindest ein Übergangsmetall und a3) Bor; b) Hydrierung der Legierung aus Schritt a) in einer wasserstoffhaltigen Atmosphäre bei Temperaturen von 0 bis 600°C und einem Wasserstoffpartialdruck von 10000 bis 15000000 Pa, unter Bildung von einkristallinen Partikeln; c) Disproportionierung der Partikel aus Schritt b) in einer wasserstoffhaltigen Atmosphäre bei Temperaturen im Bereich von größer 600 bis 1000°C bei einem Wasserstoffpartialdruck von 30000 bis 1000000 Pa; d) Desorption des Wasserstoffs und anschließende Rekombination unter Bildung isotroper Pulverpartikel; wobei es sich bei der in Schritt a) bereitgestellten Legierung teilweise oder vollständig um Altmagnetmaterial handelt. Weiterhin betrifft die vorliegende Erfindung über diese Verfahren herstellbare Pulver und deren Verwendung