Magnetic excitations in the spinel compound Lix[Mn1.96Li0.04]O4 (x=0.2,0.6,0.8,1.0): How a classical system can mimic quantum critical scaling

We present neutron-scattering results on the magnetic excitations in the spinel compounds Lix[Mn1.96Li0.04]O4 (x=0.2,0.6,0.8,1.0). We show that the dominant excitations below T?70?K are determined by Mn ions located in clusters, and that these excitations mimic the dynamic scaling found in quantum critical systems that also harbor magnetic...