The thermal and magnetic properties of uranium dioxide, a prime nuclear fuel and thoroughly studied actinide material, remain a long standing puzzle, a result of strong coupling between magnetism and lattice vibrations. The magnetic state of this cubic material is characterized by a 3-k non-collinear antiferromagnetic structure and multidomain Jahn-Teller distortions, likely related to its anisotropic thermal properties. Here we show that single crystals of uranium dioxide subjected to strong magnetic fields along threefold axes in the magnetic state exhibit the abrupt appearance of positive linear magnetostriction, leading to a trigonal distortion. Upon reversal of the field the linear term also reverses sign, a hallmark of piezomagnetism. A switching phenomenon occurs at ±18 T, which persists during subsequent field reversals, demonstrating a robust magneto-elastic memory that makes uranium dioxide the hardest piezomagnet known. A model including a strong magnetic anisotropy, elastic, Zeeman, Heisenberg exchange, and magnetoelastic contributions to the total energy is proposed.The nuclear fuel uranium dioxide is of intrinsic interest due to its industrial applications but it also exhibits intriguing electronic and magnetic properties. Here, the authors demonstrate how its complex magnetic structure and interactions give rise to a strong piezomagnetic effect.

中文翻译：

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二氧化铀中的压磁和磁弹性记忆。

二氧化铀（一种主要的核燃料和经过充分研究的act系元素材料）的热和磁性能仍然是一个长期存在的难题，这是磁力和晶格振动之间强烈耦合的结果。这种立方材料的磁态的特征在于3k非共线反铁磁结构和多畴Jahn-Teller畸变，这可能与其各向异性的热特性有关。在这里我们表明，二氧化铀的单晶在磁性状态下沿三重轴受到强磁场的影响，呈现出正线性磁致伸缩的突然出现，从而导致三角畸变。磁场反转后，线性项也将符号反转，这是压电的标志。在±18 T处会出现开关现象，这种现象在随后的磁场反转期间仍然存在，展示了一种强大的磁弹性存储器，该存储器使二氧化铀成为已知的最坚硬的压电磁体。提出了一个包含强磁各向异性，弹性，塞曼，海森堡交换和磁弹性对总能量的贡献的模型。核燃料二氧化铀由于其工业应用而备受关注，但还表现出令人着迷的电子和磁性。在这里，作者证明了其复杂的磁性结构和相互作用如何引起强烈的压电效应。核燃料二氧化铀由于其工业应用而备受关注，但它也表现出令人着迷的电子和磁性。在这里，作者证明了其复杂的磁性结构和相互作用如何引起强烈的压电效应。核燃料二氧化铀由于其工业应用而备受关注，但它也表现出令人着迷的电子和磁性。在这里，作者证明了其复杂的磁性结构和相互作用如何引起强烈的压电效应。