Structural and magnetic properties ofFe[Fe(CN)6]∙4H

Abstract

We report the structural and magnetic properties of polycrystalline ferriferricyanide, Fe͓Fe͑CN͒ 6 ͔ •4H 2 O. The room temperature neutron diffraction pattern of the sample was refined with space group Fm3m by the Rietveld refinement technique. The Mössbauer spectrum of the sample at room temperature reveals the presence of low spin Fe 3+ ͑Fe LS , S =1/2͒ and high spin Fe 3+ ͑Fe HS , S =5/2͒ ions. The compound undergoes a paramagnetic to ferromagnetic phase transition at 17.4 K. Saturation magnetization at 2.3 K corresponds to parallel ordering of Fe HS and Fe LS spin only moments in Fe͓Fe͑CN͒ 6 ͔ •4H 2 O. Neutron diffraction study at 1.5 K shows the ordered site moments of 5.0͑2͒ and 0.8͑2͒ B for Fe HS and Fe LS ions, respectively, in Fe HS ͓Fe LS ͑CN͒ 6 ͔ •4H 2 O. The coercive field of the compound is an order of magnitude higher than that of many other compounds in the Prussian Blue analog family. The observed branching between field-cooled and zero field-cooled magnetization below T C ͑=17.4 K͒ is ascribed due to magnetic domain kinetics under different cooling conditions and the presence of available vacant sites in the lattice for the water molecules.

High-pressure growth and characterization of bulk MnAs single crystals

“…A full X-ray refinement was performed at room temperature on a crystal with dimensions system where long-range magnetic ordering is involved, the upturn in the FC curve can arise from domain-wall motions and/or disorder [38,39]. Cooling under the applied magnetic field favors domain growth in the direction of applied field, thus giving higher value of magnetization.…”

Ferromagnetic order and spin-glass behavior in multi-metallic compound Ni1.125Co0.375[Fe(CN)6]·6.8H2O

“…at lower temperatures and exhibit strong irreversibility. The strong irreversible behavior of M and shift of bifurcation point to lower temperature with increasing H are characteristic for spin glasses [16,21]. In Fig.…”

Evolution of water dynamics in the Prussian blue

“…When x/y = 1, the first coordinations of A and B are A[NC] 6 and B [CN] 6 , respectively. In this case, water molecules occupy the interstitial positions [3]. However, when x/y > 1, some of the B[CN] 6 units are vacant and filled by water molecules.…”

“…Three structurally distinguishable water molecules, (i) coordinated water molecules which are coordinated at A octahedra at 24e (x, 0, 0) site, (ii) non-coordinated water molecules connected by hydrogen bonds to the coordinated ones in the spherical cavity of [B(CN) 6 ] at 32 f (x, x, x) site, and (iii) non-coordinated water at 8c (1/4, 1/4, 1/4) site of unit cell octants are found in these compounds. The structures of these compounds have been very well studied using x-ray as well as neutron diffraction techniques [3,4]. Since water plays a crucial role towards the multifunctional properties of PBA compounds, it is of interest to study their dynamical behaviour.…”