Scaling of the magnetic entropy change in chiral helimagnetic YbNiAl.

Generally, magnetic anisotropy is a common feature of a layered magnetic material, the exploration of which plays a key role in understanding the intrinsic magnetic couplings. In this work, we have studied the field-induced magnetic transitions for layered YbNiAl as the external magnetic field is applied perpendicularly ([Formula: see text]) and parallel (H//c) to the c-axis. We find that two independent universal curves of magnetic entropy change [[Formula: see text]] can be fitted out for [Formula: see text] and H//c, respectively. According to the universality principle of scaling, the extra magnetic entropy changes ([Formula: see text] and [Formula: see text]) caused by the field-induced magnetic phase transitions can be obtained for [Formula: see text] and H//c. The two-dimensional [Formula: see text] plots as functions of field and temperature are constructed, which clearly reveal the evolutions of the magnetic entropy changes resulted from the two different field-induced magnetic phase transitions. It is suggested that the [Formula: see text] for [Formula: see text] with the maximum at (3.2 K, 4.1 kOe) originates from a field-modulated helicoidal spin-texture. However, the [Formula: see text] for H//c with the maximum at (3.4 K, 13.8 kOe) stems from a field-induced canted antiferromagnetic state.