A-type antiferromagnetic order in MnBi4Te7 and MnBi6Te10 single crystals
A-type antiferromagnetic order in MnBi4Te7 and MnBi6Te10 single crystals
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DOI：
10.1103/physrevmaterials.4.054202
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发表时间：
2019-10
影响因子：
3.4
通讯作者：
Jiaqiang Yan;Jiaqiang Yan;Yaohua Liu;D. Parker;Yan Wu;A. Aczel;A. Aczel;M. Matsuda;M. McGuire-M.-Mc
中科院分区：
文献类型：
--
作者：
Jiaqiang Yan;Jiaqiang Yan;Yaohua Liu;D. Parker;Yan Wu;A. Aczel;A. Aczel;M. Matsuda;M. McGuire-M.-Mc
${\mathrm{MnBi}}_{4}{\mathrm{Te}}_{7}$ and ${\mathrm{MnBi}}_{6}{\mathrm{Te}}_{10}$ are two members with $n=2$ and 3 in the family of ${\mathrm{MnBi}}_{2n}{\mathrm{Te}}_{3n+1}$ where the $n=1$ member, ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$, has been intensively investigated as the first intrinsic antiferromagnetic topological insulator. Here we report the A-type antiferromagnetic order in these two compounds by measuring magnetic properties, electrical and thermal transport, specific heat, and single-crystal neutron diffraction. Both compounds order into an A-type antiferromagnetic structure as does ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ with ferromagnetic planes coupled antiferromagnetically along the crystallographic $c$ axis. While no evidence for any in-plane ordered moment is found for ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ or ${\mathrm{MnBi}}_{6}{\mathrm{Te}}_{10}$, weak reflections at half-$L$ positions along the [0 0 $L]$ direction are observed for ${\mathrm{MnBi}}_{4}{\mathrm{Te}}_{7}$ suggesting an in-plane ordered moment around $0.15{\ensuremath{\mu}}_{B}/\mathrm{Mn}$. The ordering temperature, ${T}_{N}$, is 13 K for ${\mathrm{MnBi}}_{4}{\mathrm{Te}}_{7}$ and 11 K for ${\mathrm{MnBi}}_{6}{\mathrm{Te}}_{10}$. The magnetic order is also manifested in the anisotropic magnetic properties. For both compounds, the interlayer coupling is weak and a spin-flip transition occurs when a magnetic field of around 1.6 kOe is applied along the $c$ axis at 2 K. As observed in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$, when cooling across ${T}_{N}$, no anomaly was observed in the temperature dependence of thermopower. On the other hand, critical scattering effects are observed in thermal conductivity although the effect is less pronounced than that in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$.
${\mathrm{MnBi}}_{4}{\mathrm{Te}}_{7}$ and ${\mathrm{MnBi}}_{6}{\mathrm{Te}}_{10}$ are two members with $n=2$ and 3 in the family of ${\mathrm{MnBi}}_{2n}{\mathrm{Te}}_{3n+1}$ where the $n=1$ member, ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$, has been intensively investigated as the first intrinsic antiferromagnetic topological insulator. Here we report the A-type antiferromagnetic order in these two compounds by measuring magnetic properties, electrical and thermal transport, specific heat, and single-crystal neutron diffraction. Both compounds order into an A-type antiferromagnetic structure as does ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ with ferromagnetic planes coupled antiferromagnetically along the crystallographic $c$ axis. While no evidence for any in-plane ordered moment is found for ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ or ${\mathrm{MnBi}}_{6}{\mathrm{Te}}_{10}$, weak reflections at half-$L$ positions along the [0 0 $L]$ direction are observed for ${\mathrm{MnBi}}_{4}{\mathrm{Te}}_{7}$ suggesting an in-plane ordered moment around $0.15{\ensuremath{\mu}}_{B}/\mathrm{Mn}$. The ordering temperature, ${T}_{N}$, is 13 K for ${\mathrm{MnBi}}_{4}{\mathrm{Te}}_{7}$ and 11 K for ${\mathrm{MnBi}}_{6}{\mathrm{Te}}_{10}$. The magnetic order is also manifested in the anisotropic magnetic properties. For both compounds, the interlayer coupling is weak and a spin-flip transition occurs when a magnetic field of around 1.6 kOe is applied along the $c$ axis at 2 K. As observed in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$, when cooling across ${T}_{N}$, no anomaly was observed in the temperature dependence of thermopower. On the other hand, critical scattering effects are observed in thermal conductivity although the effect is less pronounced than that in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$.