  We study entanglement between quantum states of multi level spin system of a
single particle considering a nucleus with spin 3/2 in both the internal
electric field gradient and the external magnetic field. It was shown that
entanglement is achieved by applying a magnetic field to a single particle at
low temperature (~ 5 mK). In this temperature range, the numerical calculation
revealed the coincidence between magnetization and concurrence. As a result,
the magnetization can be used as an entanglement witness for such systems.
