Crystal structure, absolute configuration and characteristic temperatures of SmFe 3 (BO 3 ) 4 in the temperature range 11-400 K

• Published in: Acta crystallographica Section B, Structural science, crystal engineering and materials Vol. 78; no. Pt 3 Pt 2; p. 546
• Main Authors: Smirnova, Ekaterina S, Alekseeva, Olga A, Dudka, Alexander P, Sorokin, Timofei A, Khmelenin, Dmitry N, Yapaskurt, Vasily O, Lyubutina, Marianna V, Frolov, Kirill V, Lyubutin, Igor S, Gudim, Irina A
• Format: Journal Article
• Language: English
• Published: England 01.06.2022
• Subjects: multi-temperature single-crystal X-ray diffraction; solution-melt growth; samarium bismuth iron borate; Mössbauer spectroscopy; crystal structure; absolute configuration; characteristic temperatures
• ISSN: 2052-5206
• DOI: 10.1107/S2052520622003948

The crystal structure of samarium iron borate was analyzed with regard to growth conditions and temperature. The inclusion of about 7% Bi atoms in the crystals grown using the Bi Mo O -based flux was discovered and there were no impurities in the crystals grown using the Li WO -based flux. No pronounced structural features associated with Bi inclusion were observed. The different absolute configurations of the samples grown using both fluxes were demonstrated. Below 80 K, a negative thermal expansion of the c unit-cell parameter was found. The structure of (Sm Bi )Fe (BO ) belongs to the trigonal space group R32 in the temperature range 90-400 K. A decrease in the (Sm,Bi)-O, Sm-B, Sm-Fe, Fe-O, Fe-B and Fe-Fe distances is observed with a lowering of the temperature, B1-O does not change, B2-O increases slightly and the B2O triangles deviate from the ab plane. The strongest decrease in the equivalent isotropic atomic displacement parameters (U ) with decreasing temperature is observed for atoms Sm and O2, and the weakest is observed for B1. The O2 atoms have the highest U values, the most elongated atomic displacement ellipsoids of all the atoms and the smallest number of allowed vibrational modes of all the O atoms. The largest number of allowed vibrational modes and the strongest interactions with neighbouring atoms is seen for the B atoms, and the opposite is seen for the Sm atoms. The quadrupole splitting Δ(T) of the paramagnetic Mössbauer spectra increases linearly with cooling. The Néel temperature [T  = 31.93 (5) K] was determined from the temperature dependence of the hyperfine magnetic field B (T), which has a non-Brillouin character. The easy-plane long-range magnetic ordering below T was confirmed.