Magnetic properties of NdNi \(_2\) P \(_2\) were investigated using \(^{61}\) Ni synchrotron-radiation-based Mössbauer spectroscopy. NdNi \(_2\) P \(_2\) is known to order ferromagnetically at \(T_{\mathrm C}=6.7~\textrm{K}\) with the Nd moments along the c-axis. The \(^{61}\) Ni SR-based Mössbauer spectra show slight asymmetry due to the quadrupole interaction. The absence of any clear magnetic splitting confirms that Ni does not order magnetically. The spectrum below \(T_{\mathrm C}\) shows no significant broadening, suggesting that the transferred hyperfine magnetic field from the Nd moments at the Ni site is very small. Taken together with the magnetic measurements, these results suggest that the magnetism in NdNi \(_2\) P \(_2\) arises mainly from the RKKY interaction between Nd moments.
