Fig. 2.
Domain dynamics and magnetoelastic memory in UO2. a Axial magnetostriction ε a vs. H parallel to [111] in the AFM state of UO2 in pulsed magnetic fields (T = 2.5 K). The measurement sequence is explained in the text. b Magnetostriction slope ∂ε a/∂H vs. magnetic field parallel to [111], along a strain hysteresis loop showing remanence. Lines are fits that reveal y-axis intersections α a = ±10.5 ppm T−1 and slope 2β a = 0.17 ppm T−2. c Transverse magnetostriction ε t vs. H parallel to [111] measured at T = 2.2 K in a superconducting magnet using a sequence like the one used in a. Here we observe qualitatively similar, yet opposite in sign, behavior as in ε a(H). d ∂ε t/∂H corresponding to the hysteresis loop in c showing remanence. The fitted y-axis intersections are α t = ±2.98 ppm T−1, and slope 2β t = 0.09 ppm T−2. e A partial domain reorientation effect, magnetoelastic butterfly, is obtained when magnetic fields are pulsed consecutively to fields between 5 T (red) and 14 T (purple). An equilibrium state is achieved with a 18 T pulse (orange). As seen, the domain reorientation effect can be partial, allowing for tuning of ∂ε/∂H. These characteristics make the gradual reorientation of magnetic domains a peculiar memory effect in UO2