MAGNETIC-PROPERTIES OF NICKEL AND PLATINUM QUATERNARY BOROCARBIDES

The zero-field mu(+)SR technique is employed to study the magnetic pro perties of the nonsuperconducting borocarbides Sm1-xLuxNi2B2C (z = 0.0 , 0.2) and NdPt1.5Au0.6B2C. Co- herent ordering of the Sm electronic m oments appears below T-N = 9.86(3) and 4.15(3) K for the x = 0.0 and 0 .2 compositions, respectively. No long range order of the Nd3+ moments is found in NdPt1.5Au0.6B2C down to 80 mK. Freezing of the electronic moments into a spin-glass state occurs at T-f approximate to 1.2 K. A stretched exponential decay of the mu(+) spin polarisation is observe d above T-f with the exponent beta smoothly decreasing on approaching T-f from above, reminiscent of the behaviour in other spin glasses.