Anisotropic spin-fluctuations in SmCoPO revealed by ³¹P NMR measurement

³¹P NMR spectral features in polycrystalline SmCoPO reveal an axially symmetric local magnetic field. At low temperature, the anisotropy of the internal magnetic field increases rapidly, with K _ab increasing faster than that of K _c. The dominant contribution to this anisotropy arises from Sm-4f electron contribution over that of Co-3d. The intrinsic width 2β deviates from linearity with respect to bulk susceptibility below 170 K due to the enhancement of (1=T ₂) _dynamic, which along with the continuous increase of anisotropy in the internal magnetic field is responsible for the wipe out effect of the NMR signal, well above T _C· 1=T ₁ shows large anisotropy confirming a significant contribution of Sm-4f electron spin fluctuations to 1=T ₁, arising from indirect RKKY type exchange interaction indicating a non-negligible hybridization between Sm-4f orbitals and the conduction band, over the itinerant character of the Co-3d spins. This anisotropy originates from the orientation dependence of x"(q;ω). The 3d-spin fluctuations in the ab-plane is 2D FM in nature, while along the c-axis, a signature of a weak AFM spin fluctuations superimposed on weak FM spin-fluctuations even in a field of 7T and far above T _N is observed. The enhancement of this AFM fluctuations of the Co-3d spins along c-axis, at further low temperature is responsible to drive the system to an AFM ordered state.