Magnetic-field and composition tuned antiferromagnetic instability in the quantum spin-liquid candidate <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>NaYb</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Jie Guo, Xinguo Zhao, Seiko Ohira‐Kawamura, Langsheng Ling, Junfeng Wang, Lunhua He, Kenji Nakajima, Bing Li, Zhidong Zhang
Abstract
$\mathrm{NaYb}{\mathrm{O}}_{2}$ has been reported as a possible host for the quantum spin-liquid state. Here, the composition-dependent polycrystalline $\mathrm{N}{\mathrm{a}}_{1\text{\ensuremath{-}}x}\mathrm{Yb}{\mathrm{O}}_{2}$ ($x=0$, 0.03, and 0.07) has been investigated by combining high-field magnetizations and inelastic neutron scattering techniques. For the $x=0$ sample, no signature of a magnetic order is observed down to 0.3 K. Inelastic neutron scattering measurement suggests a continuous low-energy excitation spectrum centered at momentum transfer $(Q)\ensuremath{\sim}1.25\phantom{\rule{0.16em}{0ex}}{\AA{}}^{\ensuremath{-}1}$ and extending up to energy transfer ($E$) \ensuremath{\sim} 2.0 meV. In contrast, $x=0.03$ and 0.07 samples exhibit magnetic transitions at 1.1 and 2.3 K, respectively. High-field magnetization measurements indicate similar behaviors for $x=0$ and 0.03 samples including plateaulike features at the 1/3 saturated magnetization, which implies that the spin disorder in the $x=0$ sample might be suppressed preceding the emergence of the up-up-down phase. This composition- and field-dependent study allows us to construct complete phase diagrams indicating that $\mathrm{NaYb}{\mathrm{O}}_{2}$ is a promising candidate for the quantum spin-liquid state in close proximity to the antiferromagnetic instability tuned by the application of magnetic fields as well as controlling the concentration of $\mathrm{N}{\mathrm{a}}^{+}$ ion vacancies.