UC Irvine

The results of neutron-diffraction measurements are reported which confirm the development of long-range magnetic order in superconducting NdRh4B4. Two distinct antiferromagnetic transitions occur below the superconducting phase-transition temperature TSC=5.4 K, one at TMH 1.5 K and the other at TML 1.0 K. In both phases, the body-centered tetragonal sublattice of Nd atoms orders antiferromagnetically with the Nd3+ moments aligned along the unique c axis. The magnetic moment is modulated sinusoidally along the [100] direction in the higher-temperature magnetic phase and along the [110] direction in the lower-temperature phase. The measured saturation moment is 3.4± 0.5μB. No ferromagnetic component could be detected in the higher-temperature magnetic phase within an experimental sensitivity of 0.3μB. © 1982 The American Physical Society.