  Using extensive numerical simulations, we probe the magnetization switching
in two-dimensional artificial spin ice (ASI) system consisting of peanut-shaped
nanomagnets. We also investigated the effect of the external magnetic field on
the degeneracy of the magnetic states in such a system. The switching field is
found to be one order smaller in the proposed ASI system with peanut-shaped
nanomagnets as compared to the conventionally used highly-anisotropic
nanoisland such as elliptically shaped nanomagnets. The metastable 2-in/2-out
(Type II) magnetic state is robust at the remanence. We are also able to access
the other possible microstates corresponding to Type II magnetic configurations
by carefully varying the external magnetic field. It implies that one can
control the degeneracy of the magnetic state by the application of a suitable
magnetic field. Interestingly, the magnetic charge neutrality breaks due to the
defects induced by removing nanomagnets. In such a case, the system also
appears to have a 1-out/3-in or 3-out/1-in (Type III) spin state, reminiscent
of a magnetic monopole. We believe that our study is highly desirable in the
context of developing the next-generation spintronics-based devices for future
technologies.
