We review a key subset of the experimental studies that have recently focused on cubic pyrochlore magnets whose pseudospin-1 $/$ 2 degrees of freedom have mixed dipolar and octupolar character. We discuss how this comes about and how the character of the pseudospin-1 $/$ 2 can be experimentally determined. The minimal spin Hamiltonian for such magnetic insulators is known to give rise to a rich phase diagram with both disordered U(1) quantum spin ice (QSI) states and all-in–all-out (AIAO) noncollinear ordered states, each with dipolar and octupolar character. We focus primarily on experimental studies on two such single crystal systems, the $\TimesFont{J}$ = 5 $/$ 2 Ce2Zr2O7 and the $\TimesFont{J}$ = 9 $/$ 2 Nd2Zr2O7. We make the case that Ce2Zr2O7 is an excellent QSI ground-state candidate material, close to the border between QSIs with dipolar and octupolar symmetry. Nd2Zr2O7 exhibits an AIAO ordered phase, featuring an order parameter consisting of dipolar and octupolar magnetic moments. It is found to reside close to a QSI phase boundary and features dynamic fragmentation in its excitation spectrum.

中文翻译：

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偶极子-八极焦绿石磁体中量子自旋冰物理学的实验见解


我们回顾了最近专注于立方焦绿石磁体的实验研究的一个关键子集，这些磁体的伪自旋-1 $/$ 2 自由度具有混合偶极和八极特性。我们讨论了这是如何发生的，以及如何通过实验确定伪自旋-1 $/$ 2 的特征。众所周知，这种磁绝缘体的最小自旋哈密顿量会产生一个丰富的相图，该相图具有无序的 U（1） 量子自旋冰 （QSI） 态和全进全出 （AIAO） 非共线有序态，每个态都具有偶极和八极特性。我们主要关注两个这样的单晶系统的实验研究，即 $\TimesFont{J}$ = 5 $/$ 2 Ce2Zr2O7 和 $\TimesFont{J}$ = 9 $/$ 2 Nd2Zr2O7。我们提出 Ce2Zr2O7 是一种出色的 QSI 基态候选材料，靠近具有偶极和八极对称性的 QSI 之间的边界。Nd2Zr2O7 表现出 AIAO 有序相位，其有序参数由偶极和八极磁矩组成。发现它位于 QSI 相边界附近，并在其激发光谱中具有动态碎裂。