Comparative NMR studies on Ca₃LiRuO₆and Ca₃NaRuO₆

Abstract

We report a comparative study of two ruthanate compounds, Ca3LiRuO6 and Ca3NaRuO6 by magnetic measurements, heat capacity and NMR. Ca3LiRuO6 is a weak ferromagnet with a magnetic ordering temperature of 115 K. The (7)Li NMR linewidth of Ca3LiRuO6 displays a broad shoulder above the magnetic ordering temperature. Anomalous shoulder of this type is observed in the susceptibility data also. The origin of these phenomena is not clear but could possibly be attributed to low dimensional magnetism. A contrasting magnetic behavior is seen in Ca3NaRuO6, an antiferromagnet with a transition temperature at 87 K. The NMR study shows that the Knight shift is proportional to the magnetic susceptibility. Also, in Ca3NaRuO6, the Knight shift and the linewidth of the spectra change differently compared to Ca3LiRuO6. The heat capacity of both compounds show a λ-type anomaly at respective magnetic transition temperatures. However, in both the systems the entropy change ([Formula: see text]S) is much less than that of an ordered S = 3/2 system.

Interplay of spin-orbit coupling and hybridization in Ca3LiOsO6 and Ca3LiRuO6

“…1(a), giving an identical ordering temperature for Ca 3 LiRuO 6 and Ca 3 LiOsO 6 23 . During the measurements we tested the suggestion that an anomaly above the transition temperature may be indicating a wide temperature region of short range correlations 26 . However, no such correlations were observed.…”