Thermodynamic and magnetic properties of the layered triangular magnet NaNiO2

الأصل · EN

We report muon-spin rotation, heat capacity, magnetization, and ac magnetic susceptibility measurements of the layered spin-1/2 antiferromagnet NaNiO2. These show the onset of long-range magnetic order below Tₙ = 19.5K. Rapid muon depolarization persisting to about 5K above Tₙ is consistent with the presence of short-range magnetic order. The temperature and frequency dependence of the ac susceptibility suggests that magnetic clusters persist above 25K in the paramagnetic state and that their volume fraction decreases with increasing temperature. A frequency dependent peak in the ac magnetic susceptibility at Tₛf = 3K is observed, consistent with a slowing of spin fluctuations at this temperature. A partial magnetic phase diagram is deduced.