Heavy atom ferromagnets under pressure: structural changes and the magnetic response.

Application of physical pressure to a ferromagnetic bisdiselenazolyl radical leads to a decrease in pi-stack slippage. Initially, this leads to an increase in the ferromagnetic ordering temperature T(C), which reaches a maximum of 21 K near 1 GPa. At higher pressures, as the pi-stacks become more nearly superimposed, the value of T(C) diminishes.