State-of-the-art magnetometry for quantum matter, functional materials, topological magnets and superconductors

Lead Research Organisation: Durham University
Department Name: Physics

Abstract

Magnetic phenomena in materials are some of the oldest discoveries of science and continue to be some of the technologically most widespread and useful. Despite this, an understanding of magnetism is relatively recent and is undergoing a rapid change, with key discovery of new physics, materials and applications. While all solid materials have some interaction with magnetic fields, some enjoy very strong interactions that lead to new states of matter, or properties, that can be used to sense external changes or store information. Recent examples include materials that host magnetic skyrmions, which are vortex-like patterns of magnetic moments that show promise for energy-efficient data storage, and spintronic systems where the magnetic properties of electrons can be harnessed in addition to the electronic charge. Research into novel magnetism requires the precise synthesis of complex materials followed by a detailed characterization of their properties. The topic is characterized by the rapid translation of new understandings from fundamental studies into societal applications, exemplified by advances in spintronics for the disk drive technology, that underpins cloud computing.

The ability to perform high-sensitivity magnetic studies of materials at low temperatures is essential to enable internationally-leading research in magnetism and superconductivity. The measurement of DC magnetic susceptibility is used to characterise a newly-discovered magnetic material, allowing the elucidation of magnetic properties such as the presence of phase transitions, the magnetic moment of a material or the sign of magnetic exchange. In cases where moments are not static in time, much useful information can be extracted using AC magnetic susceptibility, a technique which utilises a periodically varying magnetic field. Magnetic properties are often very dependent on the direction a field is applied with respect to the underlying material's structure, that is critical both to fundamental understanding and in device applications, requiring us to make precise measurements as a function of orientation.

The instrument commissioned under this project will allow this characterization, make it straightforwardly accessible to researchers from UK universities and industry and make it a focal point in the region. Materials measured will range from single crystals and powders of new complex oxides exhibiting diverse magnetic phenomena such as ferromagnetism, antiferromagnetism, spin-glass behaviour and skyrmions, to complex molecules used to test fundamental theories and to understand materials for spintronic applications, such as memory and sensing for "internet of things" flexible electronics. The instrument will also be key to determining the unique properties of superconductors which have enabled a step change in medical imaging using MRI scanners, and are used as components in fusion reactors. The new state-of-the-art instrument is more efficient than the old, now-obsolete models and has much-enhanced functionality needed to investigate the complex magnetic behaviour of cutting-edge materials. It will ensure the success of our users' ground-breaking research across a wide range of themes. It will feed into the research of the major facilities at STFC-ISIS and the Diamond Light Source, and will attract a wider range of users, both from the North East and across the UK.

Publications

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