$^{59}\mathrm{Co}$ and $^{31}\mathrm{P}$ nuclear magnetic resonance (NMR) measurements in external magnetic and zero magnetic fields have been performed to investigate the magnetic properties of the A-type antiferromagnetic (AFM) ${\mathrm{CaCo}}_{2}{\mathrm{P}}_{2}$. NMR data, especially the nuclear spin lattice relaxation rates $1/{T}_{1}$ exhibiting a clear peak, provide clear evidence for the AFM transition at a N\'eel temperature of ${T}_{\mathrm{N}}\ensuremath{\sim}110\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The magnetic fluctuations in the paramagnetic state were found to be three-dimensional ferromagnetic, suggesting ferromagnetic interaction between Co spins in the $\mathit{ab}$ plane characterizes the spin correlations in the paramagnetic state. In the AFM state below ${T}_{\mathrm{N}}$, we have observed $^{59}\mathrm{Co}$ and $^{31}\mathrm{P}$ NMR signals under zero magnetic field. From $^{59}\mathrm{Co}$ NMR data, the ordered magnetic moments of Co are found to be in $ab$ plane and are estimated to be 0.35 ${\ensuremath{\mu}}_{\mathrm{B}}$ at 4.2 K. Furthermore, the external field dependence of $^{59}\mathrm{Co}$ NMR spectrum in the AFM state suggests a very weak magnetic anisotropy of the Co ions and also provides microscopic evidence of canting the Co-ordered moments along the external magnetic field directions. The magnetic state of the Co ions in ${\mathrm{CaCo}}_{2}{\mathrm{P}}_{2}$ is well explained by the local-moment picture in the AFM state, although the system is metallic, as seen by $1/{T}_{1}T=\mathrm{constant}$ behavior.
原文链接
分享
引用
