Structural and magnetic properties of YNi4-Co Si alloys

This is the authors' abstract. We don't add key points for this paper.

The transition-metal based alloy system YNi4-xCoxSi shows a second-order ferromagnetic-to-paramagnetic transition near room temperature. Here, the magnetic structure, the magnetocaloric properties and the magnetic anisotropy of YNi4-xCoxSi (x = 0-4) are investigated. For x = 3.5, 3.75 and 4.0 a Curie temperature near room temperature is observed with TC = 250, 283 and 310 K, respectively. In orientated YNi4-xCoxSi powder samples the c axis of the hexagonal crystal structure is found to be the easy magnetic axis, with a large dominant K2 anisotropy constant (K2 > K1 > 0). The magnetic structure and the preferred atomic position for Ni are demonstrated by neutron diffraction measurements. We have found a dramatic decrease in the magnetic moment at the 3 g site in the CaCu5-type structure (space group P6/mmm), the saturation magnetization and the Curie temperature with increasing Ni concentration.