Synthesis and magnetic properties of rare earth ruthenates, Ln5Ru2O12 (Ln=Pr, Nd, Sm–Tb)

Stacking Faults and Short‐Range Magnetic Correlations in Single Crystal Y5Ru2O12: A Structure with Ru+4.5 One‐Dimensional Chains

“…It is noteworthy to mention that Bharathy et al observed a twinned and disordered structures for the Ln 5 Ru 2 O 12 (Ln = Eu, Gd, and Tb) compounds (but not Pr 5 Ru 2 O 12 ) and provided a detailed crystal structure refinement. [ 36 ] According to the Bharathy et al's report, the Pr 5 Ru 2 O 12 structure can be solved as an ideal disorder free structure; however, Eu, Gd, and Tb members possess disorders/defects in Ln, Ru, and O sites, which create a (0,0,1/2) shift in the unit cell compared to the disorder‐free structure. A similar disordered structure was also observed in Y 5 Re 2 O 12 , [ 37 ] and we also observed a similar disorder/defect structure in Y 5 Ru 2 O 12 (though without a twin contribution).…”

“…The crystal analyzed exhibited positional disorder of the Ru(1), Y(3), O(3), and O(4) sites, as often occurs in these systems. [ 36 ] The occupancy of the disordered components was freely refined, with the major component found to be 95.5% occupancy, and the minor component 4.5% occupancy. Crystallographic data are summarized in Table 1 , and selected interatomic distances for the major disordered component are provided in Table 2 .…”

“…In this article, we target hydrothermally synthesized Y 5 Ru 2 O 12 as a protype test compound for detailed magnetic study of rare‐earth ruthenates. [ 36–38 ] These compounds possess the unusual feature of 1D chains made from either 4 d or 5 d transition metal cations with an average oxidation state of 4.5, reminiscent of the 6H perovskites mentioned earlier. The magnetism of Ln 5 B 2 O 12 (B = Mo, Ru, Re) compounds has attracted much interest due to the presence of mixed valent 1D chains of the 4 d or 5 d ions.…”

“…The magnetism of Ln 5 B 2 O 12 (B = Mo, Ru, Re) compounds has attracted much interest due to the presence of mixed valent 1D chains of the 4 d or 5 d ions. [ 36–39 ] The compounds are made more interesting by the presence of alternating shorter and longer BB (RuRu, ReRe, or MoMo) distances. The intermediate valence state of Ru with alternating bond distances leads to complex magnetic behavior and these properties are made harder to understand due to the presence of lanthanide ions that can have large magnetic moments themselves.…”

“…It has been suggested that these shorter distances are the result of a BB bonds, which leave one unpaired electron per B 2 O 10 dimer, resulting in a spin value of S = ½ per dimer unit. In 2009, Bharathy et al reported a series of ruthenate analogs of Ln 5 Ru 2 O 12 compounds and reported some magnetic data; [ 36 ] however, all of examples contained an open‐shell rare‐earth ion, so the magnetic properties were dominated by the lanthanide ions.…”