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Fizika Tverdogo Tela, 2023 Volume 65, Issue 11, Pages 1864–1868 (Mi ftt10847)

Metals

Resonant indirect exchange interaction between localized spin states in 3D Dirac semimetal

Yu. V. Goryunov

Zavoisky Physical Technical Institute, Kazan Scientific Center of the Russian Academy of Sciences

Abstract: The paper considers the question of the exchange interaction of localized spin states of Eu impurities in the Dirac semimetal $\alpha$-Cd$_3$As$_2$ by means donor electrons originating from these impurities. Being in a state of chemical compression, the divalent europium ion is inclined, by donating an electron to the conduction band, to pass into a trivalent state with a smaller ionic radius. The existence of europium in the non-magnetic trivalent state occurs only a small part of the time. However, it leads to a slight decrease in its effective local magnetic moment and an increase in the $g$-factor due to interaction with Dirac electrons. The change in the degree of chemical compression with temperature explains the previously observed temperature dependences of the $g$-factor and EPR linewidth for impurity Eu$^{2+}$ ions ($g\sim$ 2.2 and $g\sim$ 4.4). Taken together, this indicates the presence of a crystallographically selective indirect exchange interaction between localized spins of Eu$^{2+}$ ions mediated by the donor conduction electrons.

Keywords: magnetic resonance, Dirac semimetals, magnetic impurities, exchange interaction.

Received: 09.08.2023
Revised: 08.10.2023
Accepted: 09.10.2023

DOI: 10.61011/FTT.2023.11.56538.178



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