We studied the effect of pressure P on a genuine organic bulk-ferromagnet, 2,5-difluorophenyl-α-nitronyl nitroxide (2,5-DF-PNN), in the region up to 9.2 GPa, by measuring the ac magnetic susceptibility Χac in a diamond anvil cell (DAC). The transition temperature Tc of 2,5-DFPNN at ambient pressure is 0.45 K. Tc is enhanced almost linearly against the pressure up to P ≤ 2.6 GPa, but that enhancement tends to saturate at P ≥ 2.6 GPa. Tc finally increases up to 1.36 K at P = 3.7 GPa. On the other hand, the magnitude of Χac is suppressed by the pressure, and the ferromagnetic signal finally disappears at P ≥ 4.6 GPa. We consider that the enhancement of Tc and the decrease of the magnitude of Χac are due to the increase of the two-dimensional ferromagnetic intermolecular interaction on a plane including the a-axis and the decrease of the ferromagnetic interaction along a third axis.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry