Effect of pressure on the magnetic properties of TM₃[Cr(CN)₆]₂·12H₂O

Abstract

Effect of pressure on magnetic properties of magnetic nanoparticles, based on Prussian blue analogues, were studied in pressures up to 1.2 GPa. The Mn 3 [Cr(CN) 6 ] 2 · nH 2 O and Ni 3 [Cr(CN) 6 ] 2 · nH 2 O nanoparticles were prepared by reverse micelle technique. Transmission electron microscopy images show nanoparticles with average diameter of about 3.5 nm embedded in an organic matrix. The characteristic X-ray peaks of nanoparticles are more diffused and broader. Systems of nanoparticles behave as systems of interacting magnetic particles. The Curie temperature TC is reduced from T C = 56 K for Ni-Prussian blue analogues to T C = 21 K for Ni-nanoparticles system and from TC = 65 K for Mn-Prussian blue analogues to T C = 38 K for Mn-nanoparticles system. One can explain this reduction of the Curie temperature and of the saturated magnetization µs by dispersion of nanoparticles in an organic matrix i.e. by a dilution effect. Applied pressure leads to a remarkable increase in T C for system of Mn-nanoparticles (∆T C /∆p = +13 K/GPa) and to only slight decrease in T C for system of Ni-nanoparticles (∆T C /∆p = −3 K/GPa). The pressure effect follows behavior of the mother Prussian blue analogues under pressure. The increase in saturated magnetization, attributed to compression of the organic matrix, is very small. PACS numbers: 75.30.Cr, 75.50.Ee, 75.50.Gg, 75.50.Xx (489) 490 A. Zentko et al.

The Effect of Pressure on Magnetic Properties of KMnCr(CN)6.

“…The increase in Curie temperature under pressure was ascribed to the enhancement of antiferromagnetic interaction as the consequence of the exchange pathway shortening. In our earlier work we have shown that for PBA with domination of antiferromagnetic interaction the Curie temperature increases under pressure while for those with dominating ferromagnetic it remains unchanged or slowly decreases [7]. The applied pressure can slightly affect bonding angles between magnetic ions mediated by the cyano-bridge.…”

“…The applied pressure can slightly affect bonding angles between magnetic ions mediated by the cyano-bridge. A small deviation from the ideal value 180• of the bonding angle can even reduce the strength of magnetic coupling, and results in reduction of T C [7]. Unusually high value of magnetic Grűneisen parameter ε (in the range 9.03-9.97) was reported for PBA [8].…”

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] .…”

“…In order to distinguish between these magnetic crossover mechanisms, we ventured beyond high mag- 6 ] under pressure. Combining our findings with displacement patterns and anticipated mode trends for (i) an isolated on-site high → low spin transition, (ii) a spin-lattice assisted crossover, and (iii) electron transfer (or charge ordering) induced spin transition reveals that while the spin transition takes place on the Ru dimer, it is enabled by cooperative local lattice distortions around the Cr center.…”

“…Piezomagnetism and pressure-tunable spin-orbit coupling may emerge in these systems as well. 6 ] was prepared as described previously 20 . The sample was loaded into a pressure medium like vacuum grease in order to apply quasi-hydrostatic pressure.…”