  The new $\gamma n\to K^0\Lambda$ data obtained from the CLAS and MAMI
collaborations are analyzed by employing an effective Lagrangian method. The
constructed model can describe all available experimental data in both $\gamma
p \to K^+\Lambda$ and $\gamma n\to K^0\Lambda$ channels, simultaneously. The
background part of the model is built from the appropriate intermediate states
involving the nucleon, kaon, and hyperon exchanges, whereas the resonance part
is constructed from the consistent interaction Lagrangians and propagators. To
check the performance of the model a detailed comparison between the calculated
observables and experimental data in both isospin channels is presented, from
which a nice agreement can be observed. The discrepancy between the CLAS and
MAMI data in the $\gamma n\to K^0\Lambda$ channel is analyzed by utilizing
three different models; M1, M2, and M3 that fit the CLAS, MAMI, and both CLAS
and MAMI data sets, respectively. The effect of this discrepancy is studied by
investigating the significance of individual nucleon resonances and the
predicted beam-target helicity asymmetry $E$ that has been measured by the CLAS
collaboration recently. It is found that the $N(1720)P_{13}$, $N(1900)P_{13}$,
and $N(2060)D_{15}$ resonances are significant for improving the agreement
between model calculation and data. This result is relatively stable to the
choice of the model. The helicity asymmetry $E$ can be better explained by the
models M1 and M3. Finally, the effect of the $N(1680)P_{11}$ narrow resonance
on the cross section of both isospin channels is explored. It is found that the
effect is more sensitive in the $\gamma n\to K^0\Lambda$ channel. In this case
the model M3, that fits both CLAS and MAMI data, yields a more realistic
effect.
