P31Nuclear Magnetic Resonance in the Paramagnetic State of UP

The ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$ nuclear magnetic resonance was observed in the paramagnetic state of the metallic antiferromagnet, uranium monophosphide ($T_N={123}^{\circ }\mathrm{K}$). The ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$ Knight shift measured over the temperature region 125-300°K was found to be positive, varying from $K=2\mathrm{}$ to 4%. Linearity of the $K\left(T\right)\mathrm{}-\mathrm{v}\mathrm{e}\mathrm{r}\mathrm{s}\mathrm{u}\mathrm{s}-\chi \mathrm{}\left(T\right)\mathrm{}$ relationship permitted the assignment of a ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$ hyperfine field as +21.6 kOe/(Bohr magneton). Using the Mott-Goodenough theory, the magnetic and electrical properties of UP are interpreted from a model in which the Fermi level lies in overlapping bands composed of phosphorus $s$, $p$ states and metal $6d-t_{2g}$ states.