The main results obtained in measurements of neutron magnetic form factors for rare earth systems with strong electronic correlations are presented. It is shown that in some cases neutron spectroscopy methods can provide information on the valence unstable state in the f-electron system, which is unique as regards the development of adequate physical concepts. Studies of the magnetic form factor in intermediate-valence systems based on Sm (SmB₆, SmS) and Eu (EuCu₂Si₂2 type) and their impact on the shaping of a realistic description of the physical nature of the intermediate valence state are discussed in detail.

Keywords: neutron spectroscopy, intermediate valence, magnetic form factor, strongly correlated electron systems PACS: 61.05.F−, 61.66.Dk, 75.10.−b, 75.30.Mb, 75.40.Gb (all) DOI: 10.3367/UFNe.2024.09.039748 URL: https://ufn.ru/en/articles/2025/7/b/ 2-s2.0-105013789370 2025PhyU...68..653A Citation: Alekseev P A, Lazukov V N, Savchenkov P S "Neutron magnetic form factor in studies of f-electron instability" Phys. Usp. 68 653–667 (2025) BibTexBibNote ® (generic)BibNote ® (RIS)Medline RefWorks RT Journal T1 Neutron magnetic form factor in studies of f-electron instability A1 Alekseev,P.A. A1 Lazukov,V.N. A1 Savchenkov,P.S. PB Physics-Uspekhi PY 2025 FD 10 Jul, 2025 JF Physics-Uspekhi JO Phys. Usp. VO 68 IS 7 SP 653-667 DO 10.3367/UFNe.2024.09.039748 LK https://ufn.ru/en/articles/2025/7/b/ Received: 2nd, July 2024, revised: 4th, September 2024, accepted: 9th, September 2024 Оригинал: Алексеев П А, Лазуков В Н, Савченков П С «Нейтронный магнитный формфактор в исследованиях f-электронной нестабильности» УФН 195 695–711 (2025); DOI: 10.3367/UFNr.2024.09.039748