Knight Shifts and Susceptibilities of Transition Metals: Palladium

The nuclear magnetic resonance (NMR) of ${\mathrm{Pd}}^{105}$ has been observed for the first time. The temperature dependence of the ${\mathrm{Pd}}^{105}$ NMR in palladium metal was studied in the region 1.4 to 300°K. The relatively large linewidth ($\delta H=9\mathrm{}\pm 2$ Oe) at all temperatures necessitated the use of continuous averaging techniques to obtain the requisite sensitivity. The field for resonance, at a fixed frequency, was found to have a maximum in the vicinity of 85°K, as does the susceptibility $\chi \mathrm{}\left(T\right)\mathrm{}$. From an analysis of the temperature dependence of the Knight shift $K\left(T\right)\mathrm{}$ and of $\chi \mathrm{}\left(T\right)\mathrm{}$ it was deduced that: (1) $d$-spin paramagnetism is responsible for the observed behavior of $K\left(T\right)\mathrm{}$ and $\chi \mathrm{}\left(T\right)\mathrm{}$, (2) the principle contribution to $K$ in Pd arises from $d$-spin-induced core polarization and (3) the core-polarization hyperfine field $H_{\mathrm{cp}}=-689\mathrm{}\pm 20$kOe/spin. From a partitioning of the various contributions to $K$, $\chi$, and the specific heat, an estimated value of $\frac{1}{T_1}\simeq 0.8T$ ${\sec }^{-1\mathrm{}}$ °K is obtained for the nuclear spin-lattice relaxation rate at low temperatures. It is shown that the "knee" in $\chi \mathrm{}\left(T\right)\mathrm{}$ is not associated with a static antiferromagnetic ordering; an upper limit of ${10}^{-5\mathrm{}}$ ${\mathrm{\mu }}_{\mathit{B}}$ per Pd atom for the spontaneous moment at low temperatures is obtained. A diamagnetically uncorrected value of the ${\mathrm{Pd}}^{105}$ nuclear moment ${\mu }^{105}=-0.639\mathrm{}\pm 0.003$ nm was determined.