We report ferromagnetic ordering at $T_{\mathrm{C}}=1.3\mathrm{K}$ in the quasi-two-dimensional magnet ${\mathrm{EuAl}}_{12}{\mathrm{O}}_{19}$ with large spins $S=7/2$. This ferromagnetic state was characterized by magnetization and specific heat measurements and the experimental results were compared with classical Monte Carlo simulations. They reveal a strong single-ion anisotropy leading to a uniaxial spontaneous magnetization along the $c$ axis. Furthermore, the application of a magnetic field in the hard magnetization plane $ab$ reduces the Curie temperature down to $T=0.5\mathrm{K}$ at ${\mu }_{0}H\approx 0.4\mathrm{T}$ while preserving the second-order nature of the ferromagnetic transition.

中文翻译：

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三角形磁体 EuAl12O19 中的准二维铁磁性


我们报告铁磁体 $c$ 订购于 $T_{\mathrm{C}}=1.3\mathrm{K}$ 在准二维磁体中 ${\mathrm{EuAl}}_{12}{\mathrm{O}}_{19}$ 大旋转 $S=7/2$ 。通过磁化强度和比热测量来表征这种铁磁态，并将实验结果与经典蒙特卡罗模拟进行比较。它们揭示了强烈的单离子各向异性，导致沿 c 轴的单轴自发磁化。此外，在硬磁化平面中施加磁场 $ab$ 将居里温度降低至 $T=0.5\mathrm{K}$ 在 ${\mu }_{0}H\approx 0.4\mathrm{T}$ 同时保留铁磁转变的二阶性质。