Pressure Response of Three-Dimensional Cyanide-Bridged Bimetallic Magnets

Abstract

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.

Enforcing Multifunctionality: A Pressure-Induced Spin-Crossover Photomagnet

“…Pressure-induced structural changes, especially the Mn-N bond shrinkage, increase the overlap of the respective orbitals within Nb IV -CN-Mn II structural motif and strengthens the antiferromagnetic interactions. [43][44] The photomagnetic measurements were performed for FeNb under pressure in a turnbuckle magnetic diamond anvil pressure cell (TM-DAC) [45][46] with an optical fiber for sample illumination. The initial measurements 'in the dark' at 0.03 and 0.60 GPa confirmed the same pressure-induced magnetic behavior as observed by using the CuBe cell.…”

Pressure-driven high-to-low spin transition in the bimetallic quantum magnet[Ru2(O2CMe)4]3O’Neal1, Liu2, Miller3 et al. 2014Phys. Rev. B15030View full textAdd to dashboardCite

“…These transitions can be as simple as low ↔ high spin in an isolated molecule or as complex as antiferromagnetic ↔ ferromagnetic, metamagnetic, and quantum critical processes in extended solids [2][3][4][5][6][7][8][9][10][11][12] . Spin crossovers in 4 and 5d-containing compounds are particularly interesting because spin-orbit coupling competes with electron correlations to reveal exotic properties [13][14][15][16][17][18][19] .…”

Magnetoelastic coupling in [Ru2(O2CMe)4]Brinzari1, Chen2, Tung3 et al. 2012Phys. Rev. B

“…4,5 For a molecule-based magnet in which superexchange between metal ions relies on diamagnetic ligand linkages, the interplay between spin and lattice degrees of freedom can be an important aspect for ground state stabilization. [6][7][8] Moreover, coupling often impacts how a particular state can be tuned with pressure, temperature, magnetic field, or chemical substitution. [7][8][9][10][11] [Ru 2 (O 2 CMe) 4 ] 3 [Cr(CN) 6 ] (Me=CH 3 ) attracted our attention due to its interpenetrating magnetic networks, novel spin structure, metamagnetic transition, and predicted high field spin-flop.…”

“…[6][7][8] Moreover, coupling often impacts how a particular state can be tuned with pressure, temperature, magnetic field, or chemical substitution. [7][8][9][10][11] [Ru 2 (O 2 CMe) 4 ] 3 [Cr(CN) 6 ] (Me=CH 3 ) attracted our attention due to its interpenetrating magnetic networks, novel spin structure, metamagnetic transition, and predicted high field spin-flop. 10,[12][13][14][15] These attributes combine to make this material well suited to extended investigations of magnetoelastic coupling.…”