Lu Ruie, Ji Yuanchao, Wang Yu, Ke Xiaoqin, Tian Fanghua, Zhou Chao, Zhang Yin, Liu Chang, Yang Sen, Ren Xiaobing, Song Xiaoping
School of Mechanical and Electric Engineering, Guangzhou University, Guangzhou, 510006, China.
School of Science, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
Adv Sci (Weinh). 2024 Dec;11(45):e2408517. doi: 10.1002/advs.202408517. Epub 2024 Oct 14.
The presence of Griffiths phase to cluster spin glass transition has theoretically been predicted in both classical and quantum systems. However, its detection in a classical system has been lacking for decades, which hinders a complete understanding of the relationship between the Griffiths phase and cluster spin glass. Here, the experimental discovery of the Griffiths phase to cluster spin glass transition is reported in a classical magnetic system, diluted ferromagnets LaSr(Mn Al Ti)O (0 ≤ x ≤ 0.12). The phase diagram of the system shows a transition from the Griffiths phase into a ferromagnetic state in the low disorder concentration range (0.01 < x ≤ 0.09). In the high disorder concentration range (0.09 < x ≤ 0.12), a Griffiths phase to cluster spin glass transition is identified, which nicely matches that of disordered quantum systems. Moreover, the Griffiths phase is essentially an unfrozen cluster spin glass with partially broken ergodicity is demonstrated experimentally. These findings serve as crucial experimental references for understanding the glassy phenomena in disordered magnets, facilitating future exploration of their unique properties and functionalities.
理论上已预测到在经典和量子系统中都存在从格里菲斯相到团簇自旋玻璃转变的现象。然而，几十年来一直缺乏在经典系统中对其的检测，这阻碍了对格里菲斯相与团簇自旋玻璃之间关系的全面理解。在此，报道了在经典磁系统——稀释铁磁体LaSr(Mn Al Ti)O（0 ≤ x ≤ 0.12）中从格里菲斯相到团簇自旋玻璃转变的实验发现。该系统的相图显示在低无序浓度范围（0.01 < x ≤ 0.09）内从格里菲斯相转变为铁磁态。在高无序浓度范围（0.09 < x ≤ 0.12）内，确定了从格里菲斯相到团簇自旋玻璃的转变，这与无序量子系统的转变完美匹配。此外，实验证明了格里菲斯相本质上是一种具有部分遍历性破坏的未冻结团簇自旋玻璃。这些发现为理解无序磁体中的玻璃态现象提供了关键的实验参考，有助于未来对其独特性质和功能的探索。
