Spin-glass behavior in KxRu4−yNiyO

Abstract

We report the synthesis and comprehensive AC and DC susceptibility measurements of KxRu4-yNiyO8 hollandite. The value of the relative frequency shift, δTf, has been determined as 0.025 which is within the range expected for spin-glass systems (0.005 -0.06). Additionally, the characteristic flipping time of a single spin flip, τ0, and the dynamical critical exponent, -zv were determined to have values 5.82 x 10 -8 s and 6.1(3) respectively from the Power Law. Whilst the value of τ0 is comparatively very large, -zv is consistent with what is expected for spin glass systems. Field cooled hysteresis behaviour demonstrates a small increase in the remnant magnetisation (at 2 K) on increasing the strength of the cooling field suggesting that the degree of short-range correlations increases consistent with the formation of larger spin clusters. Thermoremnant magnetisation data indicates an exponential-like decay of the magnetisation as a function of time with the remnant magnetisation remaining nonzero. However, it is clear from these data that multiple components contribute to the decay behaviour. Collectively, these data confirm spin-glass character for K0.73(3)Ni1.9(5)Ru2.1(5)O8 and clearly demonstrate that the magnetic behaviour of this material is far from simplistic.

Evidence for cluster spin glass phase with precursor short-range antiferromagnetic correlations in the B -site disordered Ca(Fe1/2Kumar1, Senyshyn2, Pandey3 2019Phys. Rev. B387210View full textAdd to dashboardCite

“…The large value of τ 0 reveals slow dynamics as expected for cluster spin glasses for which τ 0 typically lies in the range ∼ 10 −6 -10 −10 s [60,61]. Such high τ 0 values have been reported in several CSG systems [74][75][76]. For canonical SG systems like Cu:Mn, the value of τ 0 is of the order of ∼10 −13 s, which is several orders of magnitude smaller than that for the cluster spin glasses [60,61].…”