High-Field Magnet crossed the finish line at Helmholtz-Zentrum Berlin
Despite the onset of winter, the High-Field Magnet arrived in Berlin without difficulty. The magnet will be connected to the cooling facility, power supply, and the neutron guide over the next months. Photo: HZB/Phil Dera
Unloading the valuable freight: a heavy-equipment crane lifted the roughly 20-tonne High-Field Magnet from the lorry into the assembly hall. Photo: HZB/Phil Dera
The High-Field Magnet (HFM) for diffracting neutrons entered the gates of the Helmholtz-Zentrum Berlin in Wannsee on 23 January 2014 at 9am, where the project team headed by Dr. Peter Smeibidl enthusiastically accepted delivery. The journey for the roughly 20-tonne scientific device began in the Italian city of Chivasso near Turin two days prior on 21 January. It traversed its 1200 kilometre route without incident, which led through Milan, the Gotthard Tunnel, Zürich, and Stuttgart to Berlin.
The final phase of a broad and exciting project for the HZB team is now beginning: they can finally install the magnet in Berlin and connect it to the neutron guides that are in place. The team had already constructed the necessary cooling facility and power supply.
Researchers will use the new magnet to subject their specimens to a magnetic field of up to 25 teslas while irradiating them with neutrons from BER II. This is a unique capability. Up to now, neutron diffraction could only be combined with magnetic fields of up to 17 teslas. Scientists expect new insights from measurements made with the considerably more powerful magnetic field, for example in research on superconducting materials.
The development work on the High-Field Magnet began in 2007 following the signing of a joint HFM development agreement between the former Hahn-Meitner Institute and the National High Magnetic Field laboratory (MagLab) at Florida State University in Tallahassee (see Joint Development Agreement - German-only text).
The experts at MagLab have since fabricated the superconducting coil, which is the heart of the magnet (Film: The Making of a High-Field Magnet). This important stage was only completed in October 2013. The superconducting coil was carried to Europe on a transport plane (press release dated 10 Oct. 2013). Experts from the firm of Criotec in Chivasso (Italy) have developed the necessary cryostat for cooling and mounted the coil within it.
The arrival of the magnet at Helmholtz-Zentrum Berlin is a month earlier than originally planned. Before the magnet can be employed by the researchers, several steps have to be completed.
Firstly, the magnet must be set up in the assembly hall designed for it and the normal-conductivity coil installed. It is expected that the HFM will attain its maximum magnetic field strength for the first time when operating at a current of 20,000 amperes in the summer of this year. The magnet will subsequently be brought to its final location in the neutron guide hall. “There could still be a couple of stumbling blocks along the path, but we are confident that we can take these hurdles in stride”, says Dr. Hartmut Ehmler, who has coordinated the project since 2007.
The newly set-up power supply and cooling facility had been subjected to comprehensive performance tests during the past months and these are now ready for the proper magnet.
The High-Field Magnet will create magnetic fields of up to 25 tesla in the EXED neutron instrument. Magnetism plays an important role in basic research and materials science in helping us to understand the properties and behaviour of various materials. Experiments using neutrons are especially suitable for investigating magnetic structures in these materials. Researchers hope that they will discover new phenomena through the unique experiments they can conduct using extremely high magnetic fields and better understand promising materials like superconductors. The development and construction of the High-Field Magnet was approved by the German Federal Ministry of Education and Training (BMBF) in February 2007. The total scope of the investment entailed about 20 million EUR with a development and construction cycle of roughly seven years.
Links:
Film: The Making Of a Highfield Magnet
Press Release Tallahassee: MagLab to Celebrate Significant Milestone in Large-Scale Magnet Project
The HFM - Overview
- Spintronics at BESSY II: Domain walls in magnetic nanowiresMagnetic domains walls are known to be a source of electrical resistance due to the difficulty for transport electron spins to follow their magnetic texture. This phenomenon holds potential for utilization in spintronic devices, where the electrical resistance can vary based on the presence or absence of a domain wall. A particularly intriguing class of materials are half metals such as La2/3Sr1/3MnO3 (LSMO) which present full spin polarization, allowing their exploitation in spintronic devices. Still the resistance of a single domain wall in half metals remained unknown. Now a team from Spain, France and Germany has generated a single domain wall on a LSMO nanowire and measured resistance changes 20 times larger than for a normal ferromagnet such as Cobalt.
- Fractons as information storage: Not yet quite tangible, but closeA new quasiparticle with interesting properties has appeared in solid-state physics - but so far only in the theoretical modelling of solids with certain magnetic properties. An international team from HZB and Freie Universität Berlin has now shown that, contrary to expectations, quantum fluctuations do not make the quasiparticle appear more clearly, but rather blur its signature.
- Graphene on titanium carbide triggers a novel phase transitionResearchers have discovered a Lifshitz-transition in TiC, driven by a graphene overlayer, at the photon source BESSY II. Their study sheds light on the exciting potential of 2D materials such as graphene and the effects they can have on neighboring materials through proximity interactions.