A Multifunctional Magnetic Material under Pressure.

Fe-II(Metz)(6)]((FeBr4)-Br-III)(2) (Metz= 1-methyltetrazole) is one of the rare systems combining spin-crossover and long-range magnetic ordering. A joint neutron and X-ray diffraction and magnetometry study allows determining its collinear antiferromagnetic structure, and shows an increase of the Neel temperature from 2.4 K at ambient pressure, to 3.9 K at 0.95 GPa. Applied pressure also enables a full high-spin to low-spin switch at ambient temperature.