YbNiAl2YbNiAl2: A new Yb-based antiferromagnet with a field-induced ferromagnetic order

We report measurements on the thermal and magnetic properties in the temperature range 2–300 K for the YbNiAl2YbNiAl2 compound which crystallizes in the orthorhombic MgCuAl2MgCuAl2-type structure (space group Cmcm). At zero magnetic field, AC  -magnetic susceptibility data show a peak in the real component consistent with an antiferromagnetic order below TN=4.8K. A field-induced ferromagnetic order is observed from the zero field cooled and field cooled curves of DC-magnetic susceptibility at different magnetic fields with a transition to a ferromagnetic state between 9 and 10 kOe. It is further confirmed by the isothermal magnetization curves as a function of the magnetic field at several temperatures, showing two metamagnetic transitions at H1=8kOe and H2=9.3kOe. The results are compared to those reported for other Yb–Ni–Al compounds.