Syzranov S V, Ramirez A P
Physics Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA.
Nat Commun. 2022 May 30;13(1):2993. doi: 10.1038/s41467-022-30739-0.
A geometrically frustrated (GF) magnet consists of localised magnetic moments, spins, whose orientation cannot be arranged to simultaneously minimise their interaction energies. Such materials may host novel fascinating phases of matter, such as fluid-like states called quantum spin-liquids. GF magnets have, like all solid-state systems, randomly located impurities whose magnetic moments may "freeze" at low temperatures, making the system enter a spin-glass state. We analyse the available data for spin-glass transitions in GF materials and find a surprising trend: the glass-transition temperature grows with decreasing impurity concentration and reaches a finite value in the impurity-free limit at a previously unidentified, "hidden", energy scale. We propose a scenario in which the interplay of interactions and entropy leads to a crossover in the permeability of the medium that assists glass freezing at low temperatures. This low-temperature, "eminuscent", phase may obscure or even destroy the widely-sought spin-liquid states in rather clean systems.
几何阻挫（GF）磁体由局域磁矩（自旋）组成，其取向无法同时排列以最小化它们的相互作用能。这类材料可能存在新奇迷人的物相，比如被称为量子自旋液体的类流体状态。与所有固态系统一样，GF磁体含有随机分布的杂质，其磁矩在低温下可能“冻结”，使系统进入自旋玻璃态。我们分析了GF材料中自旋玻璃转变的现有数据，发现了一个惊人的趋势：玻璃转变温度随杂质浓度降低而升高，并在无杂质极限下于一个此前未识别的“隐藏”能量尺度处达到一个有限值。我们提出了一种情形，即相互作用和熵的相互作用导致介质磁导率发生转变，这有助于在低温下形成玻璃态冻结。这种低温的“减能”相可能会在相当纯净的系统中掩盖甚至破坏人们广泛探寻的自旋液体状态。
