Magnetic anisotropy of chiral magnet Yb(Ni${}_{1-x}$Cu${}_x$)${}_3$Al${}_9$ at high magnetic fields

Abstract

We have measured the magnetization of rare-earth chiral magnets Yb(Ni${}_{1-x}$Cu${}_x$)${}_3$Al${}_9$ for $x$=0 and 0.06 up to 14.5 T. Magnetization for the field direction $H\parallel c$, which is the hard axis at low temperatures and low fields, overtakes the easy axis magnetization for $H\perp c$ above $\sim$4 T. We analyzed this overtaking of the magnetization curves by considering a crystalline electric field model. It is shown that the $B_{66}$ term, which connects the $|\pm 5/2⟩$ and the $|\mp 7/2⟩$ states through the off-diagonal matrix element, is responsible for the characteristic magnetization process in this compound. We also introduce orbital dependent exchange interactions to explain the temperature dependence of magnetic susceptibility.

6 pages, 3 figures, proceedings of SCES2019