Piezomagnetic switching and complex phase equilibria in uranium dioxide

Abstract Actinide materials exhibit strong spin–lattice coupling and electronic correlations, are predicted to host new emerging ground states. One example is piezomagnetism magneto-elastic memory effect in the antiferromagnetic Mott-Hubbard insulator uranium dioxide, though its microscopic nature under debate. Here, we report X-ray diffraction studies of oriented dioxide crystals pulsed magnetic fields. In state a [888] Bragg peak follows bulk magnetostriction that expands Upon reversal field expansion turns contraction, before switching piezomagnetic ‘butterfly’ behaviour, characteristic two structures connected by time symmetry. An unexpected splitting observed, indicating simultaneous presence time-reversed domains 3-k structure complex magnetic-field-induced evolution microstructure. These findings open door for understanding across interactions.