Dresden 2020 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 52: Quantum Magnets and Molecular Magnets (joint session TT/MA)
MA 52.1: Hauptvortrag
Donnerstag, 19. März 2020, 15:00–15:30, HSZ 304
Linear magnets: a structure-property-relation for finding unquenched orbital moments — •Anton Jesche — EP VI, Center for Electronic Correlations and Magnetism, Augsburg University, 86135 Augsburg, Germany
The presence of orbital magnetic moments in rare-earth-elements is one of the major differences to transition metal compounds and is at the heart of magnetic anisotropy, stability, and functionality. A large crystal electric field effect acting on an unquenched orbital moment can lead to extremely large anisotropy and coercivity as experimentally verified for iron-doped lithium nitride [1]. In the dilute limit, those iron atoms can be considered as single-atom magnets and are ideal candidates to study the quantum dynamics of anisotropic spins [2]. This, together with the strong field dependence of the spin reversal, allows creating stable but switchable states that could act as a ’quantum bit’ at elevated temperatures of 10 K. A recent Mössbauer study revealed dominant magnetic quantum tunneling at even higher temperatures [3]. The presence of orbital moments in iron-doped lithium nitride is not a coincidence and not a solitary case: based on the proposed structural motif of the ’linear chain’, we have identified several other ’linear magnets’ with similar physical properties: iron-doped Li4SrN2, LiSr2(CoN2), (Sr6N)[FeN2][CN2]2, and K2NiO2.Implications and limitations of the linear coordination are discussed in relation to the electronic structure.
[1] M. Fix et al., PRB 97, 064419 (2018)
[2] M. Fix et al., PRL 120, 147202 (2018)
[3] S. A. Bräuninger et al., arXiv:1909.12774