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| Main Authors: | , , , , , , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2502.06422 |
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| _version_ | 1866910820243341312 |
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| author | Mohanty, S. Ranjith, K. M. Saramgi, C. S. Skourski, Y. Büchner, B. Grafe, H. -J. Nath, R. |
| author_facet | Mohanty, S. Ranjith, K. M. Saramgi, C. S. Skourski, Y. Büchner, B. Grafe, H. -J. Nath, R. |
| contents | Structural and magnetic properties of a two-dimensional spin-$\frac{5}{2}$ frustrated triangular lattice antiferromagnet NH$_{4}$Fe(PO$_{3}$F)$_2$ are explored via x-ray diffraction, magnetic susceptibility, high-field magnetization, heat capacity, and $^{31}$P nuclear magnetic resonance experiments on a polycrystalline sample. The compound portrays distorted triangular units of the Fe$^{3+}$ ions with anisotropic bond lengths. The magnetic susceptibility shows a broad maxima around $T^{\rm{max}}_χ\simeq 12$ K, mimicking the short-range antiferromagnetic order of a low-dimensional spin system. The magnetic susceptibility and NMR shift could be modeled assuming the spin-$5/2$ isotropic triangular lattice model and the average value of the exchange coupling is estimated to be $J/k_{\rm B} \simeq 1.7$ K. This value of the exchange coupling is reproduced well from the saturation field of the pulse field data. It shows the onset of a magnetic ordering at $T_{\rm N} \simeq 5.7$ K, setting the frustration ratio of $f = \frac{|θ_{\rm CW}|}{T_{\rm N}} \simeq 5.7$. Such a value of $f$ reflects moderate magnetic frustration in the compound. The d$M$/d$H$ vs $H$ plots of the low temperature magnetic isotherms exhibit a sharp peak at $H_{\rm SF} \simeq 1.45$ T, suggesting a field-induced spin-flop transition and magnetic anisotropy. The rectangular shape of the $^{31}$P NMR spectra below $T_{\rm N}$ unfolds that the ordering is commensurate antiferromagnet type. Three distinct phase regimes are clearly discerned in the $H - T$ phase diagram, redolent of a frustrated magnet with in-plane (XY-type) anisotropy. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2502_06422 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Ground state properties of a spin-$\frac{5}{2}$ frustrated triangular lattice antiferromagnet NH$_{4}$Fe(PO$_{3}$F)$_2$ Mohanty, S. Ranjith, K. M. Saramgi, C. S. Skourski, Y. Büchner, B. Grafe, H. -J. Nath, R. Materials Science Structural and magnetic properties of a two-dimensional spin-$\frac{5}{2}$ frustrated triangular lattice antiferromagnet NH$_{4}$Fe(PO$_{3}$F)$_2$ are explored via x-ray diffraction, magnetic susceptibility, high-field magnetization, heat capacity, and $^{31}$P nuclear magnetic resonance experiments on a polycrystalline sample. The compound portrays distorted triangular units of the Fe$^{3+}$ ions with anisotropic bond lengths. The magnetic susceptibility shows a broad maxima around $T^{\rm{max}}_χ\simeq 12$ K, mimicking the short-range antiferromagnetic order of a low-dimensional spin system. The magnetic susceptibility and NMR shift could be modeled assuming the spin-$5/2$ isotropic triangular lattice model and the average value of the exchange coupling is estimated to be $J/k_{\rm B} \simeq 1.7$ K. This value of the exchange coupling is reproduced well from the saturation field of the pulse field data. It shows the onset of a magnetic ordering at $T_{\rm N} \simeq 5.7$ K, setting the frustration ratio of $f = \frac{|θ_{\rm CW}|}{T_{\rm N}} \simeq 5.7$. Such a value of $f$ reflects moderate magnetic frustration in the compound. The d$M$/d$H$ vs $H$ plots of the low temperature magnetic isotherms exhibit a sharp peak at $H_{\rm SF} \simeq 1.45$ T, suggesting a field-induced spin-flop transition and magnetic anisotropy. The rectangular shape of the $^{31}$P NMR spectra below $T_{\rm N}$ unfolds that the ordering is commensurate antiferromagnet type. Three distinct phase regimes are clearly discerned in the $H - T$ phase diagram, redolent of a frustrated magnet with in-plane (XY-type) anisotropy. |
| title | Ground state properties of a spin-$\frac{5}{2}$ frustrated triangular lattice antiferromagnet NH$_{4}$Fe(PO$_{3}$F)$_2$ |
| topic | Materials Science |
| url | https://arxiv.org/abs/2502.06422 |