An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The effect of diamagnetic dilution of the Fe sublattice on the structural and magnetic properties of the double perovskite Sr{sub 2}Fe{sub 1-x}Ga{sub x}ReO{sub 6} (0 =}0.4 is detected by x-ray structural analysis accompanied by the observation of a magnetically ordered and a paramagnetic phase in the corresponding Moessbauer spectra. Below 20% Ga content, Ga statistically dilutes the -Fe-O-Re-O-Fe- double-exchange pathways. Phase separation begins at 20% Ga substitution; between 20% and 40% ofmore » Ga content, the paramagnetic Ga-based phase does not contain any Fe. The Fe-containing, paramagnetic cubic phases which can be detected by Moessbauer spectroscopy first appear for x=0.4.« less

The effect of diamagnetic dilution of the Fe sublattice on the structural and magnetic properties of the double perovskite ${\mathrm{Sr}}_{2}{\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}\mathrm{Re}{\mathrm{O}}_{6}$ $(0<x<0.7)$ has been explored by means of x-ray structural analysis, magnetometry, M\"ossbauer spectroscopy, and band structure calculations. The end member of the solid solution series, ${\mathrm{Sr}}_{2}\mathrm{Ga}\mathrm{Re}{\mathrm{O}}_{6}$, was predicted to be a half-metallic ferromagnet based on ab initio band structure calculations using the WIEN2k software package. Because the Re-containing double perovskites, like the parent compound ${\mathrm{Sr}}_{2}\mathrm{Fe}\mathrm{Re}{\mathrm{O}}_{6}$, rarely exhibit antisite disorder, the appearance of increasing amounts of antisite disorder in ${\mathrm{Sr}}_{2}{\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}\mathrm{Re}{\mathrm{O}}_{6}$ $(0<x<0.7)$ is unexpected. Although the amount of antisite disorder increases with increasing Ga content, it also depends on the sample preparation history. For $0<x<0.4$ only a tetragonal, magnetically ordered phase was detected by x-ray structural analysis as well as M\"ossbauer analysis. A phase separation into a tetragonal and a cubic phase for $x\ensuremath{\geqslant}0.4$ is detected by x-ray structural analysis accompanied by the observation of a magnetically ordered and a paramagnetic phase in the corresponding M\"ossbauer spectra. Below 20% Ga content, Ga statistically dilutes the -Fe-O-Re-O-Fe- double-exchange pathways. Phase separation begins at 20% Ga substitution; between 20% and 40% of Ga content, the paramagnetic Ga-based phase does not contain any Fe. The Fe-containing, paramagnetic cubic phases which can be detected by M\"ossbauer spectroscopy first appear for $x=0.4$.

The physical characterization of a new class of Fe(II) multifunctional SCO materials exhibiting spin crossover and liquid crystalline properties in the room temperatures region is reported. Mössbauer spectroscopy, magnetic, differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and optical polarizing microscopy studies have been performed on such materials.

The double perovskites Sr2FeMO6 (M=Re,Mo) belong to the important class of half-metallic magnetic materials. In this study we explore the effect of replacing the electronic 5d buffer element Re with variable valency by the main group element Sb with fixed valency. X-ray diffraction reveals Sr2FeRe1-xSbxO6 (0 < x < 0.9) to crystallize without antisite disorder in the tetragonally distorted perovskite structure (space group I4/mmm). The ferrimagnetic behavior of the parent compound Sr2FeReO6 changes to antiferromagnetic upon Sb substitution as was determined by magnetic susceptibility measurements. Samples up to a doping level of 0.3 are ferrimagnetic, while Sb contents higher than 0.6 result in an overall antiferromagnetic behavior. Fe-57 and Sb-121 Mossbauer spectroscopy specifies the valence state of Sb to be +5 within the whole range of substitution whereas the Fe valence state changes from +2.7 for the parent compound to +2.9 for Sr2FeRe0.1Sb0.9O6. Accordingly, Fe adopts the role of an electronic buffer element from Re upon heavy Sb doping. Additionally, Fe-57 Mossbauer results show a coexistence of ferri- and antiferromagnetic clusters within the same perovskite-type crystal structure in the Sb substitution range 0.3 < x < 0.8, whereas Sr2FeReO6 and Sr2FeRe0.9Sb0.1O6 are "purely" ferrimagnetic and Sr2FeRe0.1Sb0.9O6 contains antiferromagnetically ordered Fe sites only. Consequently, a replacement of the Re atoms by a nonmagnetic main group element such as Sb blocks the superexchange pathways -Fe-O-Re(Sb)-O-Fe- along the crystallographic axis of the perovskite unit cell and destroys the itinerant magnetism of the parent compound.

Thermochromic liquid crystals operating in the room temperature region have been successfully designed and synthesized. The reaction of 3,5-dialkoxy-N-4H-1,2,4-triazol-4-ylbenzamide ligands with Fe(4-MeC6H4SO3) 2 salt have afforded a family of complexes with the general formula [Fe(C-n-trz)(3)](4-MeC6H4SO3)(2), H2O, n being the number of carbon atoms of the alkyl chain (8 (1), 10 (2), and 12 (3)). It appears that spin-crossover (SCO) behavior occurs in the temperature range at which the materials show a discotic columnar mesophase D-hd. As a result of the ability of liquid crystals to form thin layers, it is possible to obtain thermochromic SCO films. Understanding of possible interplay/synergy between the different phase transitions occurring in these materials is still a perspective study but certainly is exciting and attractive to chemists as well as physicists.

The double perovskites Sr{sub 2}FeMO{sub 6} (M=Re,Mo) belong to the important class of half-metallic magnetic materials. In this study we explore the effect of replacing the electronic 5d buffer element Re with variable valency by the main group element Sb with fixed valency. X-ray diffraction reveals Sr{sub 2}FeRe{sub 1-x}Sb{sub x}O{sub 6} (0

The family of half-Heusler compounds offers a variety of half-metallic ferromagnetic materials. We have applied the Mössbauer spectroscopy to study the atomic order, local surroundings and hyperfine fields to several half-Heusler compounds. 121Sb Mössbauer study of the compound CoMnSb revealed the presence of two nonequivalent antimony positions in the elementary cell and enabled to identify the structure. 119mSn, 155Gd and 197Au Mössbauer spectroscopic studies were used to characterize the properties of ferromagnetic granular material based on the half-Heusler ferromagnet MnAuSn in the antiferromagnetic GdAuSn matrix.

In search of a new Prussian Blue analogue exhibiting fascinating magnetic properties, potassium manganese hexacyanoferrate, K0.2Mn0.66IIMn1.44III[Fe0.2IIFe0.8III(CN)6]O0.66(CH3COO)1.32], 7.6H2O, has been synthesized. This compound undergoes a paramagnetic to ferrimagnetic transition at 10K. Temperature and magnetic field-dependent magnetization studies of this compound have revealed different spin alignments below and above 3K. The nature of possible magnetic interactions between the nearest neighbor magnetic centers has been discussed in order to explore the origin of the observed magnetic interactions. Mössbauer spectroscopic study at different temperatures demonstrates the presence of both FeIII and FeII in low-spin states in this compound. Quantitative analysis of the FeIII and FeII ions, and their temperature dependence exhibits the existence of an electron transfer phenomenon between Mn and Fe ions [FeIII (t2g5, S=1/2)–CN–MnII (t2g3eg2, S=5/2)]⇔[FeII (t2g6, S=0)–CN–MnIII (t2g3eg1, S=2)]. This electron transfer has been remarkably enhanced in the magnetically ordered region.