Complex magnetic properties of Ho3Cu4Sn4

The Ho3Cu4Sn4 compound exhibits multiple magnetic transitions below its Néel temperature of 7.6 K. As the holmium ions occupy two different crystallographic positions (2d and 4e) a complex magnetic phase diagram was expected. Former neutron diffraction measurements revealed the existence of at least three different magnetic phases. In order to investigate the phase diagram of the Ho3Cu4Sn4 compound in more detail magnetometric, specific heat, transport and high-resolution neutron diffraction measurements were carried out. The specific heat data indicate the occurrence of five magnetic transitions at temperatures of 2.3 K, 3.3 K, 4.4 K, 5.5 K and 7.6 K, which turned out to be in a strict agreement with our new neutron diffraction data. The 2d and 4e rare-earth sublattices order independently at 7.6 K and 3.3 K, respectively. The sublattices are described by different propagation vectors which change with the temperature.