R. I. Leatherbury (University of South Alabama)
Cs_4 [Pt (C N)_4](C F_3 S O_3)_2 (TCP) is a new Krogmann's salt, consisting of quasi-one-dimensional conducting chains of Pt with well known properties, especially in the potassium-containing material, KCP. Unlike KCP, however, there are properties unique to TCP, e.g., longer Pt-Pt separation, insulating at room temperature, and non-magnetic. Previous NMR studies on KCP have mainly been on 195Pt, which does not produce a usable NMR signal in TCP; our study utilizes 133Cs instead, which are peripheral to the Pt chains. Splitting of spin states due to quadrupole interaction with local electric field gradient has been measured as a function of orientation versus applied static field. Modeling of the frequency shifts reveals consistency with the known symmetry axes of 133Cs determined by single-crystal x-ray diffraction. Relaxation time T1 versus temperature reveals a weak relaxation mechanism and absence of magnetism. Relaxation data has a sharp anomaly around 119 K where T1 jumps 3 orders of magnitude, consistent with critical fluctuations but not yet well understood.
A. P. Reyes (National High Magnetic Field Laboratory) A. P. Weber (University of South Alabama) Albert Gapud (University of South Alabama) J. Alexander (University of South Alabama) L. Pham (University of South Alabama) O. Gafarov (University of South Alabama) P. Kuhns (National High Magnetic Field Laboratory) R. E. Sykora (University of South Alabama)