Magnetic, thermodynamic and transport properties at the first and second order magnetic phase transitions in Dy5Si3 compound

We present extended studies including the dc and ac magnetic susceptibility, magnetization, specific heat, electrical resistivity and magnetoresistivity measurements for the Dy5Si3 compound with the hexagonal Mn5Si3-type structure. The results indicate that this compound orders antiferromagnetically below TN=137 K. The magnetic properties of Dy5Si3 are mainly governed by the presence of the magnetic moments of Dy3+ ions. In the paramagnetic range, the magnetic susceptibility follows the Curie–Weiss law with μeff=10.57 μB/Dy, which is very close to the theoretical value of 10.6 μB. From the magnetometric, specific heat and transport data it has been found that below 50 K this compound reveals a non-collinear magnetic order, associated with a phase transition, probably of the first order type. On the basis of the thermodynamic approach, we report the magnetocaloric properties in the whole temperature range but concentrate mainly on the region around 50 K. The magnetocaloric effect was calculated in terms of the isothermal magnetic entropy change ΔSM as well as the adiabatic temperature change ΔTad using the specific heat data. In spite of the only moderate ΔSM values a significant relative cooling power has been observed.

► Dy5Si3 orders antiferromagnetically below TN=137 K.
► Below 50 K it reveals a non-collinear antiferromagnetic-like behavior, associated with a first-order phase transition.
► Complex magnetic structure.
► A significant relative cooling power has been observed.