Coexistence of Anomalous Hall Effect and Weak Net Magnetization in Collinear Antiferromagnet MnTe

Anomalous Hall effect (AHE) plays important role in the rapidly developing field of antiferromagnetic spintronics. It has been recently discussed that it can be a feature of not only uncompensated magnetic systems but also in altermagnetic materials. Hexagonal MnTe belongs to this appealing group of compounds exhibiting AHE and is commonly perceived as magnetically compensated. Here, we demonstrate that bulk form of MnTe exhibits small but detectable magnetic moment correlating with hysteretic behaviour of the AHE. We formulate a phenomenological model which explains how this feature allows to create a disbalance between states with opposite N\'eel vector and prevent the AHE signal from averaging out to zero. Moreover, we show how the dependence of AHE on the N\'eel vector arises on microscopical level and highlight the differences in Berry curvature between magnetically compensated and uncompensated systems

New approaches for magnetic diagnostic of future fusion devices

New approaches for magnetic diagnostic of future fusion devicesI. Ďuran1, S. Entler1, K. Kovařík1, A. Torres1,11, P. Turjanica2, J. Reboun2, L. Viererbl3, D. Najman1,4, M. Kočan5, G. Vayakis5, K. Výborný6, Z. Šobáň6, M. Kohout6, V. Mortet6, A. Taylor6, P. Moreau7, F.P. Pellissier7, A. Le-Luyer7, P. Spuig7, W. Biel8, T. Franke9,101Institute of Plasma Physics of the CAS, Praha, Czech Republic2Faculty of Electrical Engineering, University of West Bohemia, Plzeň, Czech Republic3Research Centre Rez, 250 68 Husinec-Řež, Czech Republic4Czech Technical University in Prague, Praha, Czech Republic5ITER Organization, St Paul Lez Durance Cedex, France6Institute of Physics of the CAS, Praha, Czech Republic7IRFM, CEA, F-13108 Saint Paul lez Durance, France8Institut für Energie und Klimaforschung, Forschungszentrum Jülich GmbH, Germany9EUROfusion Power Plant Physics and Technology (PPPT) department, Garching, Germany10Max-Planck-Institut für Plasmaphysik, Garching, Germany11Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, PortugalThis contribution will review main challenges associated with the deployment of magnetic diagnostic for the EU DEMO fusion reactor, starting from return of experience from ITER, particularly in terms of operational temperature, neutron loads, required accuracy, and limited maintainability. New approaches to local magnetic field sensors design and construction will be introduced, namely metal-ceramic Hall sensors and inductive sensors manufactured using Thick Printed Copper (TPC) technology. Key lessons learned from the process of development, manufacturing, and calibration of ITER outer vessel steady state magnetic diagnostic based on bismuth Hall sensors will be outlined. The development of steady state magnetic sensors for a DEMO reactor is an even more challenging task compared to the ITER sensor system primarily due to approximately two orders of magnitude higher life time neutron fluence at envisaged sensor locations and also due to the higher operational temperature of the sensors. An outlook on some of the perspective design solutions for steady state magnetic sensors tackling the more demanding DEMO requirements will be given. Special attention will be paid to the design of the Hall sensors control electronics, and advanced methods of signal detection which are essential to ensure accurate detection of inherently low output voltages of Hall sensors in the noisy environment of a fusion reactor. Regarding inductive sensors, TPC technology will be introduced as an alternative to Low Temperature Co-fired Ceramics (LTCC) technology for the manufacturing of inductive local magnetic field sensors for DEMO and for their proof-of-principle application in COMPASS-U tokamak. Finally, potential synergy between steady state and traditional inductive approaches of local magnetic field measurements will be highlighted