Motivated by the strong magnetoelectric coupling in the multiferroic geometrically frustrated triangular antiferromagnet $\mathrm{Cu}\mathrm{Cr}{\mathrm{O}}_2$ and the high sensitivity of its magnetic structure to external fields, we investigate induced magnetic phases at very low temperatures under high magnetic fields ($B$) up to 325 T applied along the [001] direction. Analytical calculations and Monte Carlo (MC) simulations based on a realistic three-dimensional classical Heisenberg model are used to reveal these magnetic phases. Interestingly, our model mimics a real distorted crystal which considers exchange interactions up to third-nearest neighbors in the $ab$ plane and an interplane interaction, in addition to hard and easy axes anisotropies along the [110] and the [001] directions, respectively. For $B\ge 70\mathrm{T}$, both our MC and analytical results are in an excellent agreement and evidence three commensurate phases, namely, the commensurate Y (CY), the up-up-down (UUD), and the V phases as the magnetic field increases. The field dependence of the characteristic angles of the CY and V phases is determined. Moreover, the saturation field is estimated at 325 T, indicating that the previously predicted values obtained by extrapolation of experimental data are too small. Below 70 T, our MC results indicate that the CY phase is no more stable and several incommensurate Y phases appear. Overall, the observed magnetic phases at nearly 0 K are in a good agreement with a recently published experimental phase diagram. It should be noted that our MC data reject the incommensurate umbrella phase at very low temperatures, which was reported in previous studies.

中文翻译：

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CuCrO2中的磁场感应相：蒙特卡洛和分析研究

由强铁磁耦合在多铁几何受阻的三角反铁磁体中产生 $铜铬{\mathrm{Ø}}_{\mathrm{2个}}$ 以及它的磁性结构对外部磁场的高灵敏度，我们研究了在强磁场下在非常低的温度下的感应磁相（$乙$）沿[001]方向施加的最大载荷为325T。基于现实的三维经典海森堡模型的分析计算和蒙特卡洛（MC）仿真用于揭示这些磁相。有趣的是，我们的模型模仿了一个真实的扭曲晶体，该晶体考虑了交换相互作用，直到晶体中最接近第三的邻居为止。$\mathrm{一种}b$除了分别沿[110]和[001]方向的硬轴和易轴各向异性之外，平面和平面间的相互作用。为了$乙\ge 70\mathrm{Ť}$，我们的MC和分析结果都非常吻合，并证明了三个相应的阶段，即，随着磁场的增加，相应的Y（CY），上下（UUD）和V相。确定了CY和V相特征角的场相关性。此外，在325 T处估计了饱和场，这表明通过外推实验数据获得的先前预测值太小。低于70 T，我们的MC结果表明CY相不再稳定，出现了几个不相称的Y相。总体而言，在近0 K处观察到的磁相与最近发表的实验相图非常吻合。应该注意的是，我们的MC数据拒绝了在非常低的温度下不适当的伞状相，这在先前的研究中已有报道。