Abstrakt
Magnetism in alpha-NdIr(2)Si(2) single crystals has been probed through specific-heat, magnetization, magnetic susceptibility, and electrical resistivity measurements as a function of temperature, under an applied magnetic field, and for the magnetization curves under high hydrostatic pressures. Neutron diffraction experiments performed with powder and single-crystal samples were focused on microscopic aspects.
Two collinear (Nd moments along the c axis) antiferromagnetic phases are found at low temperatures: a longitudinal sine-modulated structure with the magnetic propagation vector k = (0 0 5/6) at temperatures 18.2(2) K { T { 32.3(3) K (+T(N)) and a simple AF1-type structure; k = (0 0 1/2) for T { 18.2(2) K (+T(t)). Both of the magnetically ordered phases can be destabilized by applying a strong magnetic field along the c axis.
The character of the unusual magnetic-field-induced phases is discussed, and the complex magnetic phase diagram is constructed. Applied hydrostatic pressure yields an increase of both TN and Tt.
The determined physical properties of a-NdIr2Si2 are discussed in the context of behavior of alpha-PrIr(2)Si(2).