Strongly Quenched Kramers Doublet Magnetism in SmMgAl11O19

Fuente: arXiv
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Main Authors: Kumar, Sonu, Salajová, Barbora, Kancko, Andrej, Corrêa, Cinthia A., Halder, Shuvajit, Colman, Ross H.
Format: Preprint
Published: 2026
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author Kumar, Sonu
Salajová, Barbora
Kancko, Andrej
Corrêa, Cinthia A.
Halder, Shuvajit
Colman, Ross H.
author_facet Kumar, Sonu
Salajová, Barbora
Kancko, Andrej
Corrêa, Cinthia A.
Halder, Shuvajit
Colman, Ross H.
contents We report magnetic susceptibility, isothermal magnetization, and specific-heat measurements on the rare-earth hexaaluminate SmMgAl$_{11}$O$_{19}$, where Sm$^{3+}$ realizes a strongly quenched Kramers doublet on a triangular lattice with an exceptionally weak net exchange scale. The Curie--Weiss analysis yields strongly reduced ground-doublet $g$ factors, $g_{ab}\simeq 0.65$ and $g_{c}\simeq 0.70$. This indicates that the low-temperature response is governed primarily by single-ion physics, with crystal-field splitting and $J$-multiplet mixing jointly renormalizing the Sm$^{3+}$ moment, rather than collective exchange. For $H \parallel c$, the specific heat shows no $λ$-type anomaly down to 0.35~K but evolves into a well-defined two-level Schottky peak whose gap grows linearly with field, yielding $g_c\simeq0.62$ and recovering nearly all of $R\ln2$ at high fields, thereby confirming an effective $S_{\mathrm{eff}}=\tfrac12$ Kramers doublet description for $T\lesssim10$~K. Together, these results establish SmMgAl$_{11}$O$_{19}$ as a weak-exchange, nearly single-ion triangular Kramers magnet in which frustration produce an anisotropic low-field correlated regime without inducing long-range order.
format Preprint
id arxiv_https___arxiv_org_abs_2601_13439
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Strongly Quenched Kramers Doublet Magnetism in SmMgAl11O19
Kumar, Sonu
Salajová, Barbora
Kancko, Andrej
Corrêa, Cinthia A.
Halder, Shuvajit
Colman, Ross H.
Strongly Correlated Electrons
Materials Science
We report magnetic susceptibility, isothermal magnetization, and specific-heat measurements on the rare-earth hexaaluminate SmMgAl$_{11}$O$_{19}$, where Sm$^{3+}$ realizes a strongly quenched Kramers doublet on a triangular lattice with an exceptionally weak net exchange scale. The Curie--Weiss analysis yields strongly reduced ground-doublet $g$ factors, $g_{ab}\simeq 0.65$ and $g_{c}\simeq 0.70$. This indicates that the low-temperature response is governed primarily by single-ion physics, with crystal-field splitting and $J$-multiplet mixing jointly renormalizing the Sm$^{3+}$ moment, rather than collective exchange. For $H \parallel c$, the specific heat shows no $λ$-type anomaly down to 0.35~K but evolves into a well-defined two-level Schottky peak whose gap grows linearly with field, yielding $g_c\simeq0.62$ and recovering nearly all of $R\ln2$ at high fields, thereby confirming an effective $S_{\mathrm{eff}}=\tfrac12$ Kramers doublet description for $T\lesssim10$~K. Together, these results establish SmMgAl$_{11}$O$_{19}$ as a weak-exchange, nearly single-ion triangular Kramers magnet in which frustration produce an anisotropic low-field correlated regime without inducing long-range order.
title Strongly Quenched Kramers Doublet Magnetism in SmMgAl11O19
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2601.13439