Quenching Effects on Topological Defects in Magnetoelectric CuO Nanoparticles

CuO stands out among the few identified binary multiferroic materials, boasting a transition temperature of about 230 K — a value notably higher than other materials. In CuO, electric polarization emerges due to spontaneous magnetic order. Even a minimal application of magnetic fields can induce a transition from the paraelectric to a ferroelectric phase, observed at 213 K [1]. Interestingly, topological defects in such materials exhibit remarkably different properties at the nanoscale compared to their bulk counterparts [2]. Bragg coherent diffractive imaging has proven to be a reliable method for the three-dimensional characterization of nanoscale ferroelectrics [3,4]. By integrating magnetic quenching with Bragg Coherent Diffractive Imaging on CuO nanoparticles, we successfully investigated the nanocrystal's structural alterations and how they relate to the material's ferroelectric landscape.<br/>References:<br/> <br/>[1] Wang, Z., Qureshi, N., Yasin, S. et al. Magnetoelectric effect and phase transitions in CuO in external magnetic fields. Nat Commun 7, 10295 (2016). https://doi.org/10.1038/ncomms10295<br/>[2] X. Shi, N. P. Nazirkar, R. Kashikar, et al. Enhanced piezoelectric<br/>response at nanoscale vortex structures in ferroelectrics arXiv preprint arXiv:2305.13096 (2023).<br/>[3] Karpov, D., Liu, Z., Rolo, T. <i>et al.</i> <i> Nat Commun</i> <b>8</b>, 280 (2017). https://doi.org/10.1038/s41467-017-00318-9<br/>[4] D. Karpov, Z. Liu, A. Kumar, B. Kiefer, R. Harder, T. Lookman, and E. Fohtung, Phys. Rev. B 100, 054432 – Published 22 August 2019<br/> <br/><b>Acknowledgments</b><br/>We acknowledge support from the US Department of Energy (DOE), Office of Science, under grant No. DE-SC0023148. E.F. also acknowledges support from the US Department of Defense, Air Force Office of Scientific Research (AFOSR), under award No. FA9550-23-1-0325 (Program Manager: Dr. Ali Sayir) for work on probing topological vortices and piezoelectric enhancements. This research used resources of the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility, operated for the DOE Office of Science by Argonne National Laboratory (ANL) under contract No. DE-AC02-06CH11357.