Vortex lattice of highly anisotropic layered superconductors in strong, parallel magnetic fields

The equations for the gauge-invariant phases obtained in the framework of the Lawrence-Doniach model are used to study the vortex lattice in layered superconductors in strong, parallel magnetic fields H. As H changes, a sequence of first-order phase transitions occurs between the lattices with different periods. The largest jumps in magnetization, of order Hc1, occur at fields of order H₀=φ₀/{γ}s², where φ₀ is the flux quantum, s is the interlayer spacing, and {γ} is the anisotropy ({γ}=λc/λab, where λc and λab are the penetration depths for currents perpendicular and parallel to the layers, respectively). The asymptotic dependence of the magnetization M at high fields H{}H₀ is M{∝}H^-3.