Zero-field NMR and NQR measurements of the antiferromagnet URhIn ₅

The antiferromagnet URhIn₅ with the Néel temperature T_N=98 K has been investigated by nuclear magnetic/quadrupole resonance (NMR/NQR). 115In-NQR spectra in the paramagnetic state give the respective electrical field gradient parameters for the locally tetragonal and orthorhombic In(1) and In(2) sites. In the antiferromagnetic state at 4.5 K, 115In-NMR spectra in the zero external field indicate a commensurate antiferromagnetic structure. The internal field at In(1) sites is found to be zero and that at In(2) sites is 21.1 kOe at 4.5 K. The temperature (T) dependence of the nuclear relaxation rates 1/T₁ in the paramagnetic state shows a distinct site dependence: Korringa-type constant ⁽T₁T^)-1 behavior below ∼150 K for In(1) sites and a divergent behavior of 1/T₁ toward T_N for In(2). The plausible antiferromagnetic structure is discussed based on these observations.