Temperature dependences of the magnetic moment have been measured in ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ thin films over a wide magnetic-field range $(5\mathrm{}<~H<~{10}^4\mathrm{Oe}).\mathrm{}$ In these films a paramagnetic signal known as the paramagnetic Meissner effect has been observed. The experimental data in the films, which have strong pinning and high critical current densities ${(J}_c\sim 2\times {10}^6{\mathrm{A}/\mathrm{c}\mathrm{m}}^2$ at 77 K), are shown to be highly consistent with the theoretical model proposed by Koshelev and Larkin [Phys. Rev. B 52, 13 559 (1995)]. This finding indicates that the origin of the paramagnetic effect is ultimately associated with nucleation and inhomogeneous spatial redistribution of magnetic vortices in a sample which is cooled down in a magnetic field. It is also shown that the distribution of vortices is extremely sensitive to the interplay of film properties and the real experimental conditions of the measurements.

• Received 27 June 2003

DOI:https://doi.org/10.1103/PhysRevB.69.024506