Pressure Response of Three-Dimensional Cyanide-Bridged Bimetallic Magnets

Effects of pressure on the structures and magnetic properties of three types of 3-D cyanide-bridged bimetallic coordination polymer magnets, MnIICrIII ferrimagnet [Mn(en)]3[Cr(CN)6]2·4H2O (1; en =
ethylenediamine), NiIICrIII ferromagnet [Ni(dipn)]3[Cr(CN)6]2·3H2O (2; dipn = N,N-di(3-aminopropyl)amine),
and NiIIFeIII ferromagnet [Ni(dipn)]2[Ni(dipn)(H2O)][Fe(CN)6]2·11H2O (3), were systematically examined under
hydrostatic pressure up to 19.8 GPa using a piston-cylinder-type pressure cell and a diamond anvil cell.
The ferrimagnet 1 showed the reversible crystalline-to-amorphous-like phase change, and the magnetic
phase transition temperature (TC) was reversibly changed from 69 K at 0 GPa to 126 K at 4.7 GPa. At
higher pressure, the net magnetization was suppressed with increasing pressure, and the magnetic state
at 19.8 GPa was assumed to be paramagnetic. The initial ferrimagnetic phase of 1 was not recovered
after releasing the pressure from 19.8 GPa. The magnetic phase of 2 was reversibly converted between
ferromagnetic and paramagnetic-like phase in the range 0 ≤ P ≤ 4.7 GPa while maintaining its crystallinity.
The porous ferromagnet 3 was easily amorphized and irreversibly lost the ferromagnetic phase under low
pressure (P ≤ 1.0 GPa). The flexible cyanide-bridged magnetic frameworks demonstrate well the pressure
response as a reflection of differences in the magnetic structure and the framework strength in the GPa
range.