Dimensionality inbis-Tetramethylselenafulvalenium Hexafluorophosphate,(TMTSF)2PF6

Abstract

The dimensionality of the spin dynamics in bis-tetramethylselenafulvalenium hexafluorophosphate ${\mathrm{}\left(\mathrm{TMTSF}\right)\mathrm{}}_2$P${\mathrm{F}}_6$, is studied in the high-pressure metallic phase at low temperatures via the field dependence of proton relaxation rates. Two regimes are identified: a low-field regime (1-12 kOe) where the relaxation rate is independent of field and a highfield regime (12-120 kOe) where the relaxation rate depends logarithmically on field. The high-field behavior is interpreted as spin dynamics in a quasi two-dimensional metal with a crossover to three-dimensional spin dynamics at low field.