Magnetication vs external magnetic field in layered superconductors

Maslov S.S., Pokrovsky V.L.

**For an anisotropic layered superconductor we have calculated the magnetization ve absolute value ***é ***and orientation of the external magnetic field. It displays a cusp at a field ***Μ = Χι(θ), ***where ***θ ***is the angle between the field and the layers, and a maximum at some characteristic field ***X ***= #**_{s}(0) α (sini)^{-1} in agreement with the experimental meaeurments by Zavaritsky N.V. and Zavaritsky V.N. **We predict the existence of an intermediate critical field ***Μ = Μ*_{3}{θ) **ÏÓ (sinfl)**^{-1 }at which the perpendicular to the layers component of the magnetic induction first penetrates the sample. The magnetic susceptibility *χ = Äí/Äè ***has a jump at ***N ***= The jump is very small at ***× ***> 7**^{_1}, where 7 is the anisotropy **coefficient. In this range of angles one can observe a cusp on a graph of χ vs )( at ***ë = U^***This prediction of theory is in good agreement with the experiment **^{a}.