Opposite pressure effects on magnetic phase transitions in NiBr2

Fuente: arXiv
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Autores principales: Qureshi, Parvez Ahmed, Pokhrel, Krishna Kumar, Prchal, Jiri, Ray, Subhasmita, Arapan, Sergiu, Carva, Karel, Sechovsky, Vladimir, Pospisil, Jiri
Formato: Preprint
Publicado: 2025
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author Qureshi, Parvez Ahmed
Pokhrel, Krishna Kumar
Prchal, Jiri
Ray, Subhasmita
Arapan, Sergiu
Carva, Karel
Sechovsky, Vladimir
Pospisil, Jiri
author_facet Qureshi, Parvez Ahmed
Pokhrel, Krishna Kumar
Prchal, Jiri
Ray, Subhasmita
Arapan, Sergiu
Carva, Karel
Sechovsky, Vladimir
Pospisil, Jiri
contents NiI2 and NiBr2 are archetypal van der Waals (vdW) triangular-lattice multiferroics that host incommensurate helimagnetic order at the lowest temperatures and undergo a transition to collinear antiferromagnetic order upon heating. Focusing on NiBr2, we reveal that both antiferromagnetic phases exhibit a pronounced sensitivity to hydrostatic pressure. The Neel temperature of the collinear phase increases steeply at 20 K/GPa, reaching 100 K at 3 GPa without any indication of saturation, whereas the helimagnetic phase is completely suppressed only above 0.8 GPa. This behavior contrasts sharply with NiI2, in which both helical and collinear phases are strengthened until a moderate pressure of 6 GPa, above which the helical phase instantly disappears. Ab initio calculations identify the second-nearest interlayer exchange interaction (j2') as the primary driver stabilizing the collinear AFM phase in NiBr2. In addition, the in-plane exchange ratio renders the helical order in NiBr2 considerably more fragile, enabling its suppression under relatively small pressures. These results underscore the dominant role of interlayer interactions in governing the distinct pressure responses of the magnetic phases in NiBr2 and NiI2.
format Preprint
id arxiv_https___arxiv_org_abs_2506_04933
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Opposite pressure effects on magnetic phase transitions in NiBr2
Qureshi, Parvez Ahmed
Pokhrel, Krishna Kumar
Prchal, Jiri
Ray, Subhasmita
Arapan, Sergiu
Carva, Karel
Sechovsky, Vladimir
Pospisil, Jiri
Materials Science
Strongly Correlated Electrons
NiI2 and NiBr2 are archetypal van der Waals (vdW) triangular-lattice multiferroics that host incommensurate helimagnetic order at the lowest temperatures and undergo a transition to collinear antiferromagnetic order upon heating. Focusing on NiBr2, we reveal that both antiferromagnetic phases exhibit a pronounced sensitivity to hydrostatic pressure. The Neel temperature of the collinear phase increases steeply at 20 K/GPa, reaching 100 K at 3 GPa without any indication of saturation, whereas the helimagnetic phase is completely suppressed only above 0.8 GPa. This behavior contrasts sharply with NiI2, in which both helical and collinear phases are strengthened until a moderate pressure of 6 GPa, above which the helical phase instantly disappears. Ab initio calculations identify the second-nearest interlayer exchange interaction (j2') as the primary driver stabilizing the collinear AFM phase in NiBr2. In addition, the in-plane exchange ratio renders the helical order in NiBr2 considerably more fragile, enabling its suppression under relatively small pressures. These results underscore the dominant role of interlayer interactions in governing the distinct pressure responses of the magnetic phases in NiBr2 and NiI2.
title Opposite pressure effects on magnetic phase transitions in NiBr2
topic Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2506.04933