DQMP Forum - Determining the Phase Diagram of Atomically Thin Layered Antiferromagnet CrCl3 - X-ray Tomography Analysis of High-performance Nb3Sn Wires for FCC

05.05.2020 13:00 – 14:30

Determining the Phase Diagram ofAtomically Thin Layered Antiferromagnet CrCl3
Zhe Wang (Group Prof. Morpurgo)

Changes in the spin configuration of atomically thin, magnetic van der Waals multilayers can cause drastic modifications in their opto-electronic properties. Conversely, the opto electronic response of these systems provides information about the magnetic state, which is very difficult to obtain otherwise. Here, we show that in CrCl3 multilayers, the dependence of the tunnelling conductance on applied magnetic field, temperature and number of layers tracks the evolution of the magnetic state, enabling the magnetic phase diagram to be determined experimentally. Besides a high-field spin-flip transition occurring for all thicknesses, the in-plane magnetoconductance exhibits an evenodd effect due to a low-field spin-flop transition. Through a quantitative analysis of the phenomena, we determine the interlayer exchange coupling as well as the layer magnetization and show that in CrCl3 shape anisotropy dominates. Our results reveal the rich behaviour of atomically thin layered antiferromagnets with weak magnetic anisotropy.


X-ray Tomography Analysis of High-performance Nb3Sn Wires for FCC
Tommaso Bagni (Group. Prof. Senatore)

High-performance Restacked-Rod-Process (RRP) Nb3Sn wires are the key technology in order to achieve 16 T magnetic field necessary to explore the new energy frontier of the Future Circular Collider (FCC). In high field and high current conditions, the superconducting wires experience stresses that may lead to the degradation of the electrical transport properties of Nb3Sn wires. Among other aspects, the degradation is related to the presence of voids in the wires. These voids are generated during the wire heat treatment necessary to form the Nb3Sn superconductive phase. Several RRP wires were measured at the X-Ray Microtomography beamline of the European Synchrotron Radiation Facility in order to investigate the voids properties. The tomography reconstruction highlights the presence of two void types in the Nb3Sn sub-elements and in the copper matrix. Their different impact on the wire performance is discussed.

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