  We propose a feasible scheme to realize nonlinear Ramsey interferometry with
a two-component Bose-Einstein condensate, where the nonlinearity arises from
the interaction between coherent atoms. In our scheme, two Rosen-Zener pulses
are separated by an intermediate holding period of variable duration and
through varying the holding period we have observed nice Ramsey interference
patterns in time domain. In contrast to the standard Ramsey fringes our
nonlinear Ramsey patterns display diversiform structures ascribed to the
interplay of the nonlinearity and asymmetry. In particular, we find that the
frequency of the nonlinear Ramsey fringes exactly reflects the strength of
nonlinearity as well as the asymmetry of system. Our finding suggests a
potential application of the nonlinear Ramsey interferometry in calibrating the
atomic parameters such as scattering length and energy spectrum.
