Spin dynamics in the new Pr-pyrochlore Pr2Pt2O7

Pr-based pyrochlores Pr2B2O7 (where B = Sn, Zr, Hf) have been considered as U(1) spin liquid, candidates because they do not show long-range magnetic order down to tens of mK. We have successfully synthesized polycrystalline samples of a new Pr-pyrochlore Pr2Pt2O7 using a high-pressure technique. Heat capacity measurements show a peak at ~150 mK attributed to either magnetic order, spin freezing, or a Schottky anomaly, while the ac susceptibility vs temperature data exhibit a frequency-dependence in both the real and imaginary components which is reminiscent of glassy freezing with some persistent dynamics. We propose to carry out muon spectroscopy experiments using MuSR to investigate the spin dynamics in this new Pr-pyrochlore Pr2Pt2O7.

基于镨的烧绿石（pyrochlore）型化合物Pr₂B₂O₇（其中B代表锡（Sn）、锆（Zr）、铪（Hf））曾被视为U(1)自旋液体（U(1) spin liquid）的候选材料，这是因为在低至数十毫开尔文的温度下，该类材料未表现出长程磁有序。我们采用高压合成技术，成功制备出一种新型镨基烧绿石Pr₂Pt₂O₇的多晶样品。热容测量结果显示，该样品在约150毫开尔文处出现特征峰值，该现象可归因于长程磁有序、自旋冻结或肖特基反常（Schottky anomaly）；而交流磁化率的温度依赖数据表明，其信号的实部与虚部均呈现频率依赖性，这一特征让人联想到伴随持续动力学过程的玻璃态冻结行为。我们提议开展采用MuSR技术的μ子光谱实验，以探究该新型镨基烧绿石Pr₂Pt₂O₇中的自旋动力学特性。