Topological magnetic phase transition in Eu-based A -type antiferromagnets
| Autor: | Eliot Heinrich, Thore Posske, Benedetta Flebus |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Physical Review B. 106 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.106.214402 |
| Popis: | Recently, a colossal magnetoresistance (CMR) was observed in EuCd$_2$P$_2$ -- a compound that does not fit the conventional mixed-valence paradigm. Instead, experimental evidence points at a resistance driven by strong magnetic fluctuations within the two-dimensional ($2d$) ferromagnetic (FM) planes of the layered antiferromagnetic (AFM) structure. While the experimental results have not yet been fully understood, a recent theory relates the CMR to a topological vortex-antivortex unbinding, i.e., Berezinskii-Kosterlitz-Thouless (BKT), phase transition. Motivated by these observations, in this work we explore the magnetic phases hosted by a microscopic classical magnetic model for EuCd$_2$P$_2$, which easily generalizes to other Eu A-type antiferromagnetic compounds. Using Monte Carlo techniques to probe the specific heat and the helicity modulus, we show that our model can exhibit a vortex-antivortex unbinding phase transition. We find that this phase transition displays the same sensitivity to in-plane magnetization, interlayer coupling, and easy-plane anisotropy that is observed experimentally in the CMR signal, providing qualitative numerical evidence that the effect is related to a magnetic BKT transition. Comment: 8 pages, 4 figures |
| Databáze: | OpenAIRE |
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