Magnetic properties of nickel and platinum quaternary borocarbides

The zero-field μSR technique is employed to study the magnetic properties of the nonsuperconducting borocarbides Sm1−xLuxNi2B2C (x = 0.0, 0.2) and NdPt1.5Au0.6B2C. Coherent ordering of the Sm electronic moments appears below TN = 9.86(3) and 4.15(3) K for the x = 0.0 and 0.2 compositions, respectively. No long range order of the Nd moments is found in NdPt1.5Au0.6B2C down to 80 mK. Freezing of the electronic moments into a spin-glass state occurs at Tf ≈ 1.2 K. A stretched exponential decay of the μ spin polarisation is observed above Tf with the exponent β smoothly decreasing on approaching Tf from above, reminiscent of the behaviour in other spin glasses.