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Low Temperature Piezomagnetism on UO2

September 29, 2016 - 2:00pm to 3:30pm
Marcelo Jaime
Los Alamos National Lab

Uranium dioxide is, by far, the most thoroughly studied actinide material and it is a key component in nuclear energy applications. Its elastic and magnetic properties, however, remain an unsolved puzzle resulting from the intertwining of magnetic interactions among U-atoms and dynamic Jahn-Teller distortions of O-atoms [1]. In this opportunity I will discuss magnetostriction data taken in the low temperature paramagnetic and antiferromagnetic states to magnetic fields in excess of 90T at the National High Magnetic Field Laboratory. I will show that its linear magnetostriction in the antiferromagnetic state makes UO2 a piezomagnet, confirming a thirty-year-old prediction [2, 3]. During the course of this research we also found that antiferromagnetic domains in UO2 show persistent magnetoelastic memory that require external magnetic fields in excess of 18 T to be aligned, a formidable resilience to external magnetic fields 10x larger than in other known piezomagnets [4]. The unusually strong correlations between the magnetic moments in U-atoms and lattice distortions are a direct consequence of the non-collinear symmetry of the magnetic state, and could have consequences in the thermophysical properties of this technologically important material [5].


1. Santini, P., Carretta, S., & Amoretti, G., Multipolar interactions in f-electron systems: The paradigm of actinide dioxides. Rev. Mod. Phys. 81, 807 (2009).

2. Bar’yakhtar, V.G., Vitebskii, I.M., & Yablonskii D. A., Magnetoelastic effects in noncollinear antiferromagnets Zh. Eksp. Teor. Fiz. 89, 189 (1985).

3. Dzialoshinskii, I.E., The Problem of Piezomagnetism J. Exptl. Theoret. Phys. (U.S.S.R.) 33, 807 (1957).

4. Borovik-Romanov, A.S., Piezomagnetism, Linear Magnetostriction and Magnetooptic Effect Ferroelectrics 162, 153 (1993).

5. Jaime, M. et al., to be published.

1201 John S. Toll Physics Bldg.