Variable range hopping conductivity in Y123–Y211 composites close to the percolation limit

The normal state resistivity of the Y₁₂₃–Y₂₁₁ percolation system is best represented by a variable range hopping (VRH) model in which the electronic states of the system are localized. The characteristic temperature T₀, in the VRH representation ρ=ρ₀(T₀/T)¼ has been used to deduce the hopping length (α⁻¹) and we find that as the percolation limit is approached α⁻¹ decreases

Spin reorientation in GdAl2?

It is shown that a number of previously unexplained features of the 27Al NMR spectrum in the cubic Laves compound GdAl2 can be understood if it is assumed that the direction of preferred magnetization changes from a [221] to a [111] axis as the temperature is raised from 4.2 to 77 K.</p