AC susceptibility and specific heat studies on the successive antiferromagnetic orderings in NdCu 6

Abstract

The magnetic behavior of NdCu 6 displays successive magnetic phase transitions below the Néel temperature T N = 6.1 K. We have studied the successive antiferromagnetic order by the synchronous measurements of ac magnetic susceptibility and specific heat in magnetic fields (up to 5 T) applied to the three crystallographic axes. The magnetic susceptibility data along the c-axis show four steep jumps at 6.10, 5.82, 5.74 and 5.58 K at zero magnetic field. These are in agreement with the four successive peaks of the specific heat. The thermal hysteresis of the susceptibilities indicates that three of the transitions are of the first order except for the anomaly of 6.10 K. Magnetic phase diagrams were derived from these measurements.