Absence of Induced Ferromagnetism in Epitaxial Uranium Dioxide Thin Films

التفاصيل البيبلوغرافية
العنوان: Absence of Induced Ferromagnetism in Epitaxial Uranium Dioxide Thin Films
المؤلفون: Thomas, William, Wilhelm, Fabrice, Langridge, Sean, Harding, Lottie. M, Bell, Christopher, Springell, Ross, Friedemann, Sven, Caciuffo, Roberto, Lander, Gerrard. H
سنة النشر: 2024
المجموعة: Condensed Matter
مصطلحات موضوعية: Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons
الوصف: Recently, Sharma et al. [Adv. Sci. 9, 2203473 (2022)] claimed that thin films (around 20 nm) of UO2 deposited on perovskite substrates exhibit strongly enhanced paramagnetism (called induced ferromagnetism by the authors). Moments of up to 3 Bohr magneton/U atom were claimed in magnetic fields of 6 T. We have reproduced such films and, after characterisation, have examined them with X-ray circular magnetic dichroism (XMCD) at the uranium M edges, a technique that is element specific. We do not confirm the published results. We find a small increase, as compared to the bulk, in the magnetic susceptibility of UO2 in such films, but the magnetisation versus field curves, measured by XMCD, are linear with field and there is no indication of any ferromagnetism. The absence of any anomaly around 30 K (the antiferromagnetic ordering temperature of bulk UO2) in the XMCD signal suggests the films do not order magnetically.
نوع الوثيقة: Working Paper
URL الوصول: http://arxiv.org/abs/2402.00546
رقم الأكسشن: edsarx.2402.00546
قاعدة البيانات: arXiv