High spin (5T2)-low spin (1A1) equilibrium of iron (II) in M2FeSn3S8 thiospinels (M = Cu, Ag)

Rapid Cooling Experiments and Use of an Anionic Nuclear Probe to Sense the Spin Transition of the 1D Coordination Polymers [Fe(NH2trz)3]SnF6⋅n H2O (NH2trz=4‐amino‐1,2,4‐triazole)

“…Indeed, to the best of our knowledge, there is only one series of materials on which a combined Mçssbauer study could be feasible, namely, the thiospinels M 2 FeSn 3 S 8 (M + = Cu, Ag) that were reported to exhibit a HS$LS spin equilibrium at T 1/2 % 200 K, as deduced from magnetic susceptibility and 57 Fe Mçssbauer spectroscopy measurements. [47] The rigid lattice of this solid-state compound should allow a variable-temperature 119 Sn Mçssbauer study and provide insights into the spin conversion of these solid-state materials.…”

Thermal low spin–high spin equilibrium of Fe(II) in thiospinels CuFe0.5(Sn(1−x)Tix)1.5S4 (0≤x≤1)

“…It may be concluded from the Mössbauer spectra that at this temperature all iron is in the HS state. Hence, according the w m T versus T plot, the transition from the LS to the HS state extends over approximately 550 degrees, which is somewhat more than the 400 degrees reported previously in studies based on a rather low number of data points and in which the plateau zone was delimited with less accuracy [11,12]. The point of equal populations of the HS and LS states is reached at T 1/2 ¼210 K, i.e., at the temperature at which the slope of the curve increases considerably.…”

“…The unusual magnetic properties of CuFe 0.5 Sn 1.5 S 4 and AgFe 0.5 Sn 1.5 S 4 were first investigated by Padiou et al [12] and were later identified by 57 Fe Mössbauer spectroscopy as a spin crossover of iron(II) [11]. In CuFe 0.5 Sn 1.5 S 4 Cu(I) ions occupy the tetrahedral sites while Fe(II) and Sn(IV) ions are found in random distribution on the octahedral sites of the spinel lattice [13], which will be described in more details in Section 3.…”

“…However, corresponding examples exhibiting a LS-HS crossover are extremely scarce compared to the large number of metal-organic complexes. Examples of this kind are the perovskites La 1 À x Sr x CoO 3 (see, e.g., the review in [9]), the compounds Fe x Ta 1 À x S 2 for xr1/3 [10] and the spinels CuFe 0.5 Sn 1.5 S 4 and AgFe 0.5 Sn 1.5 S 4 [11].…”

Kinetics of Solid-State Synthesis of Quaternary Cu2FeSnS4 (Stannite) Nanocrystals for Solar Energy Applications

“…Figure 4 shows that the magnetization values for M (H) curves taken at 300 K are well-saturated after the application of magnetic fields with the magnitude higher than 1 T. In principle, the magnetic data can also be used for progress evaluation of reaction (2). The final products of this reaction, namely stannite and rhodostannite, are weak magnetic (paramagnetic) substances at a room temperature [11,20]. Therefore, the differences in the saturation magnetization of the samples milled for different times are caused mainly by the different amount of the non-consumed iron, which is the only ferromagnetic component in these materials at 300 K. For longer milling times, the saturation magnetization rapidly decreases, indicating that significant amount of elemental Fe has been already consumed by the mechanochemical reaction.…”