Magnetic transition and spin dynamics in the triangular Heisenberg antiferromagnetα-KCrO2

Abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We present the results of muon-spin relaxation measurements on the triangular lattice Heisenberg antiferromagnet α-KCrO 2 . We observe sharp changes in behavior at an ordering temperature of T c = 23 K, with an additional broad feature in the muon-spin relaxation rate evident at T = 13 K, both of which correspond to features in the magnetic contribution to the heat capacity. This behavior is distinct from both the Li-and Na-containing members of the series. These data may be qualitatively described with the established theoretical predictions for the underlying spin system.

Universal fluctuating regime in triangular chromate antiferromagnets

“…4) suggests another magnetic instability at T * 12 K that coincides with the temperature at which the ZFC and FC susceptibilities bifurcate. This feature is quite similar to that reported for CuCrO 2 and α-KCrO 2 previously [24,47].…”

“…On the other hand, α-HCrO 2 with the shortest interlayer distance was recently claimed to evade magnetic order and lie in the vicinity of a spin-liquid phase [23]. Using a combination of thermodynamic and local probes applied to α-HCrO 2 , we show that in fact all these chromates -NaCrO 2 , α-HCrO 2 , as well as α-KCrO 2 [24] -develop a very similar phenomenology. They enter a broad uni-versal fluctuating regime below T N , followed by the formation of a static and likely incommensurate spin state below T * .…”

Magnetism of the A -site ordered perovskites CaCu3Cr4O12 and L

“…Nevertheless, μ + SR measurements demonstrated the presence of static magnetic order in LaCu 3 Cr 4 O 12 [4]. This clearly indicates the importance of μ + SR for studying magnetic ground states of complex oxides, as already shown for other chromium compounds [12][13][14][15][16][17][18][19].…”

Partially disordered spin structure in Ag2CrO2studied withμ+SR

“…In order to discuss the magnetic nature of Ag 2 CrO 2 , it is helpful to know the situation of related layered chromium dioxides, such as, LiCrO 2 , NaCrO 2 , and KCrO 2 . According to ND measurements, 26 LiCrO 2 is known to enter into an almost ideal 120 • structure characteristic of the nearestneighbor Heisenberg model on a two-dimensional triangular lattice below T N = 61.2 K. This was supported by other measurements [27][28][29] including μ + SR. 30,31 On the other hand, NaCrO 2 lacks long-range magnetic order down to the lowest T measured, but shows an onset of gradual freezing at T f = 41 K. 32,33 For KCrO 2 , which was very recently synthesized, 34 susceptibility and heat capacity measurements indicated the presence of an AF transition at 23 K. Therefore, besides KCrO 2 , due to absence of information on the AF spin structure, 35 the interlayer coupling between Cr moments through Li or Na is very weak compared with the in-plane coupling. Furthermore, first-principles calculations predict that the interlayer coupling in LiCrO 2 is AF.…”