Reviews of topical problems

V.V. Val’kov, D.M. Dzebisashvili, M.M. Korovushkin, A.F. Barabanov “Spin-polaron concept in the theory of normal and superconducting states of cuprates” Phys. Usp. 64 641–670 (2021)

A.G. Syromyatnikov, S.V. Kolesnikov, A.M. Saletsky, A.L. Klavsyuk “Formation and properties of metallic atomic chains and wires” Phys. Usp. 64 671–701 (2021)

A.M. Balagurov, I.S. Golovin “Neutron scattering in studies of Fe-based functional alloys (Fe—Ga, Fe—Al)” Phys. Usp. 64 702–721 (2021)

Instruments and methods of investigation

V.M. Petrov, P.M. Agruzov, V.V. Lebedev, I.V. Il’ichev, A.V. Shamray “Broadband integrated optical modulators: achievements and prospects” Phys. Usp. 64 722–739 (2021)

Bibliography

E.V. Zakharova “New books on physics and related sciences” Phys. Usp. 64 740–742 (2021)

Physics news on the internet

Yu.N. Eroshenko “Physics news on the Internet (based on electronic preprints)” Phys. Usp. 64 743–745 (2021)