Paramagnetic probes to study PrNi5?

The Van-Vleck paramagnet PrNi5 has been the focus of many studies in the past as a result of its usefulness as a nuclear cooling agent. Extensive continuous wave praseodymium NMR measurements have been carried out on this compound. However pulsed NMR and therefore precise relaxation measurements particularly at mK temperatures have proved elusive. In this work we have proposed to use radiative gamma-ray detection to indirectly measure Pr NMR in PrNi5 via cross relaxation to suitable paramagnetic impurity probes placed at Ni lattice sites. 57Co was chosen as the most compatible nuclear orientation isotope with an appropriate nuclear g-factor. The choice of 57Co also allows the use of Moessbauer spectroscopy to check the site occupancy. This poster details the production of a 57Co doped PrNi5 single crystal specimen including the specimen preparation problems encountered, 57Fe Moessbauer and preliminary nuclear orientation measurements