New aspects on URu2Si2 and CeTIn5 (T = Rh, Ir, Co) observed by high pressure NMR and NQR

摘要

NMR and NQR studies on two interesting systems (URu2Si2, CeTIn5) were performed under high pressure. (1) URu2Si2: In the pressure range 3.0 to 8.3 kbar, we have observed new 29Si NMR signals arising from the antiferromagnetic (AF) region besides the previously observed 29Si NMR signals which come from the paramagnetic (PM) region in the sample. This gives de???nite evidence for spatially-inhomogeneous development of AF ordering below e?‘?0 of 17.5 K. The volume fraction is enhanced by applied pressure, whereas the value of internal ???eld (a?? 91 mT) remains constant up to 8.3 kbar. In the AF region, the ordered moment is about one order of magnitude larger than 0.03 e???e??μ. (2) CeTIn5: The pressure and temperature (e?‘?) dependences of nuclear spin-lattice relaxation rate 1/e?‘?1 of 115In in CeTIn5 have shown that the superconductivity (SC) occurs close to an AF instability. From the e?‘? dependences of 1/e?‘?1 and Knight shift below e?‘?c, CeTIn5 has been found to exhibit non-e?‘? wave (probable e?‘‘ wave) SC with even parity and line nodes in the SC energy gap.