Magnetic vortices observed in haematite

Magnetic vortices observed in antiferromagnetic haematite were transferred into ferromagnetic cobalt.

Vortices are common in nature, but their formation can be hampered by long range forces. In work recently published in Nature Materials, an international team of researchers has used mapped X-ray magnetic linear and circular dichroism photoemission electron microscopy to observe magnetic vortices in thin films of antiferromagnetic haematite, and their transfer to an overlaying ferromagnetic sample. Their results suggest that the ferromagnetic vortices may be merons, and indicate that vortex/meron pairs can be manipulated by the application of an in-plane magnetic field, giving rise to large-scale vortex–antivortex annihilation. Ferromagnetic merons can be thought of as topologically protected spin ‘bits’, and could potentially be used for information storage in meron racetrack memory devices, similar to the skyrmion racetrack memory devices currently being considered.

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Image: Graphic outlining the antiferromagnetic rust vortices. The grayscale base layer represents the (locally collinear) magnetic order in the rust layer, and the coloured arrows the magnetic order imprinted into the adjacent Co layer.

New forensic DNA profiling technique on the horizon

A study recently conducted at the Circular Dichroism beamline (B23) here at Diamond Light Source could pave the way to a new forensic DNA profiling technique. Researchers hailing from the Ivanovo State University of Chemistry and Technology, Russia, The University of Southampton and Diamond investigated the application of specially designed DNA building blocks.

DNA is a versatile template that can be used for a variety of applications. It is made up of building blocks known as nucleotides (labelled A, C, G and T) which form long strands that bind to complementary sequences and give the familiar double helix. The nucleotides can be tailor made to build new functional molecules for biotechnology, analytics, or even materials science.

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With help from a few friends

Researchers discover the precise make-up of a molecular chaperone complex

A complex made up of three proteins, Hsp90, Sgt1, and Rar1, is thought to stabilise an important immune protein known as nucleotide-binding domain and leucine-rich repeat containing protein. While the structure of the Sgt1-Hsp90-Rar1 protein is known, the stoichiometry of the complex has remained elusive. In a paper published in Frontiers in Molecular Biosciences, Dr Chrisostomos Prodromou of the University of Sussex and Dr Minghao Zhang of the University of Oxford worked with Professor Giuliano Siligardi at the Circular Dichroism beamline (B23) at Diamond Light Source to clarify the detailed make-up of the complex. Using synchrotron radiation circular dichroism, they revealed that it consists of an Hsp90 dimer, two Sgt1 molecules, and a single Rar1 molecule. The stoichiometry of the full complex potentially allows two NLR molecules to bind, a finding which may open avenues of research into how these proteins form dimers.

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Figure: (extract) The structure of the Sgt1-Hsp90-Rar1 complex with an Hsp90 dimer, two Sgt1 molecules, and a single Rar1. Entire image here.