Department of Physics Govt. P.G. College Bageshwar Uttarakhand India

Email:-dmpsc@rediffmail.com

The present work deals with the study of penetration depth as a function of temperature and various other microscopic interactions that exit in bilayer high temperature cuprate superconducting materials. For this, we consider a tight binding bilayer Hubbard Hamiltonian that includes the in-plane(within CuO₂ plane) and out-of-plane interactions and employ Green's function technique to describe various correlations, important in superconductivity phase. The expressions for superconducting order parameters, carrier density and penetration depth are obtained. The numerical analysis shows that in bilayer cuprates the penetration depth depends on various in-plane and out-of-plane contributions as well as on temperature in an essential way. Finally, we have compared our theoretical results on penetration depth with that of recent experimental findings and found to be in qualitative agreement.