Magnetic imaging of a supercooling glass transition in a weakly disordered ferromagnet
Magnetic imaging of a supercooling glass transition in a weakly disordered ferromagnet
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DOI：
10.1038/nmat1743
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发表时间：
2006-11-01
期刊：
影响因子：
41.2
通讯作者：
De Lozanne, Alex
中科院分区：
文献类型：
--
作者：
Wu, Weida;Israel, Casey;De Lozanne, Alex
自旋玻璃是在微观磁相互作用的挫折性和随机性中发现的。它们是非遍历系统，其中副本对称性被打破。虽然已经在许多巨大的磁阻锰氧化物中观察到了磁性玻璃行为，但没有人一致认为它们是自旋玻璃。在这里，一个有趣的玻璃化转变(La，Pr，Ca)MnO_3是用变温磁力显微镜成像。与推测的自旋玻璃图相反，我们的结果表明，在玻璃化转变温度以下观察到的静态磁组态来自于一级反铁磁(电荷有序)到铁磁转变的协同冻结。我们的数据还表明，调节应变在相变动力学中是重要的。这种合作冻结的想法已被应用于包括窗户玻璃和过冷液体在内的结构玻璃，并可能适用于许多系统，适用于发生在复杂自由能景观上的任何一级相变。
Spin glasses are founded in the frustration and randomness of microscopic magnetic interactions. They are non-ergodic systems where replica symmetry is broken. Although magnetic glassy behaviour has been observed in many colossal magnetoresistive manganites, there is no consensus that they are spin glasses. Here, an intriguing glass transition in ( La, Pr, Ca)MnO3 is imaged using a variable-temperature magnetic force microscope. In contrast to the speculated spin-glass picture, our results show that the observed static magnetic configuration seen below the glass-transition temperature arises from the cooperative freezing of the first-order antiferromagnetic ( charge ordered) to ferromagnetic transition. Our data also suggest that accommodation strain is important in the kinetics of the phase transition. This cooperative freezing idea has been applied to structural glasses including window glasses and supercooled liquids, and may be applicable across many systems to any first-order phase transition occurring on a complex free-energy landscape.