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Main Authors: Kim, Seo-Jin, Jirák, Zdeněk, Hejtmánek, Jiří, Knížek, Karel, Rosner, Helge, Ahn, Kyo-Hoon
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2412.04685
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author Kim, Seo-Jin
Jirák, Zdeněk
Hejtmánek, Jiří
Knížek, Karel
Rosner, Helge
Ahn, Kyo-Hoon
author_facet Kim, Seo-Jin
Jirák, Zdeněk
Hejtmánek, Jiří
Knížek, Karel
Rosner, Helge
Ahn, Kyo-Hoon
contents The stability and magnonic properties of double-layered antiferromagnets are investigated using two model systems, a linear chain (LC) and a more complex chain of railroad trestle (RT) geometry, and the results are confronted with properties of the real material CrN. The spin-paired order ($\cdots{+}{+}{-}{-}\cdots$) in LC requires alternating ferromagnetic and antiferromagnetic (AFM) exchanges, whereas in RT, an analogous order remains stable even when all interactions are AFM within certain analytical constraints. The rock-salt structure of CrN evokes clear magnetic frustration since Cr atoms in a face-centered cubic lattice form links to twelve nearest neighbors (NNs) all equivalent and AFM. Nonetheless, the magnetostructural transition to an orthorhombically distorted phase below $T_\text{N} = 287~\text{K}$ leads to four different NN Cr-Cr distances and consequently, to a large diversification of the exchange strength, which suppresses the frustration and allows for stable double-layered AFM order of CrN. This behavior originates from a competition at each NN link between Cr-Cr direct exchange and 90$^\circ$ Cr-N-Cr superexchange, both exhibiting specific power-law dependences on the interatomic distance. Finally, based on the $\textit{ab initio}$ calculated exchange parameters, the magnon spectrum and temperature evolution of ordered magnetic moments are derived.
format Preprint
id arxiv_https___arxiv_org_abs_2412_04685
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Semiclassical model of magnons in double-layered antiferromagnets
Kim, Seo-Jin
Jirák, Zdeněk
Hejtmánek, Jiří
Knížek, Karel
Rosner, Helge
Ahn, Kyo-Hoon
Strongly Correlated Electrons
The stability and magnonic properties of double-layered antiferromagnets are investigated using two model systems, a linear chain (LC) and a more complex chain of railroad trestle (RT) geometry, and the results are confronted with properties of the real material CrN. The spin-paired order ($\cdots{+}{+}{-}{-}\cdots$) in LC requires alternating ferromagnetic and antiferromagnetic (AFM) exchanges, whereas in RT, an analogous order remains stable even when all interactions are AFM within certain analytical constraints. The rock-salt structure of CrN evokes clear magnetic frustration since Cr atoms in a face-centered cubic lattice form links to twelve nearest neighbors (NNs) all equivalent and AFM. Nonetheless, the magnetostructural transition to an orthorhombically distorted phase below $T_\text{N} = 287~\text{K}$ leads to four different NN Cr-Cr distances and consequently, to a large diversification of the exchange strength, which suppresses the frustration and allows for stable double-layered AFM order of CrN. This behavior originates from a competition at each NN link between Cr-Cr direct exchange and 90$^\circ$ Cr-N-Cr superexchange, both exhibiting specific power-law dependences on the interatomic distance. Finally, based on the $\textit{ab initio}$ calculated exchange parameters, the magnon spectrum and temperature evolution of ordered magnetic moments are derived.
title Semiclassical model of magnons in double-layered antiferromagnets
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2412.04685