AI 中文总结
研究Ce$_2$Sn$_2$O$_7$的零场长程有序及磁场相图。通过水热技术生长单晶并测量热容量，发现零场下T~0.04 K有一级转变，解决是否有QSI基态的争论，还发现自旋冰物理相关，磁场下异常有变化，丰富了相图。
AI 中文摘要
在烧绿石磁体Ce$_2$X$_2$O$_7$（其中X = Zr、Hf或Sn）中，Ce$^{3 + }$伪自旋 - 1/2自由度具有偶极 - 八极特性。成功描述其性质的XYZ最近邻模型哈密顿量使它们成为量子自旋冰基态的有吸引力候选者。我们报告了对通过水热技术生长的高质量Ce$_2$Sn$_2$O$_7$单晶进行的极低温度下的新热容量测量。我们的零场测量揭示了在T~0.04 K时向长程有序的明显一级转变，远低于更广泛的类肖特基异常的下降，这是铈烧绿石零场热容量的常见特征。这一观察解决了关于Ce$_2$Sn$_2$O$_7$在零场中是否具有QSI基态的争论——它不具有。然而，我们也发现了令人信服的证据表明自旋冰物理在附近，并且与Ce$_2$Sn$_2$O$_7$相关。沿[1,1,0]方向施加磁场会导致这个峰在更高温度下演变为更具连续平均场转变特征的弱异常。在沿[1,1,0]的更高场中，类肖特基异常分叉，类似于经典自旋冰中独立极化的α和正交β链的预期。这些新的实验结果证明了基于铈的烧绿石相图的丰富性。
英文摘要
The Ce$^{3+}$ pseudospin-1/2 degrees of freedom in the pyrochlore magnets Ce$_2$X$_2$O$_7$, with $X$ = Zr, Hf, or Sn, possess dipole-octupole character. The XYZ nearest-neighbor model Hamiltonians which have successfully described their properties make them attractive candidates for quantum spin ice ground states. We report new heat capacity measurements to very low temperatures on a high-quality single crystal of Ce$_2$Sn$_2$O$_7$ grown by hydrothermal techniques. Our zero-field measurements uncover a clear first order transition to long-ranged order at $T \sim 0.04$ K, well below the downturn in the broader Schottky-like anomaly that is a common feature in the zero-field heat capacity for cerium pyrochlores. This observation settles the debate as to whether Ce$_2$Sn$_2$O$_7$ possesses a QSI ground state in zero field - it does not. However, we also find compelling evidence suggesting that spin ice physics is nearby, and remains relevant to Ce$_2$Sn$_2$O$_7$. Application of a magnetic field along the $[1,1,0]$ direction leads to an evolution of this peak to a weak anomaly at higher temperature more characteristic of a continuous, mean field transition. At higher fields along $[1,1,0]$, the Schottky-like anomaly bifurcates similar to expectations for independent polarized $α$ and orthogonal $β$ chains in classical spin ice. These new experimental results demonstrate richness to the phase diagram for Ce-based pyrochlores.
CommentsMain Text (5 pages, 4 figures), Supplemental Material (6 pages, 4 figures)
