demagnetization factor was better characterized ($N \approx 3.2$ (cgs units)), and the value at the $M/H$ plateau did match with the $1/N$ value, confirming the ferromagnetic nature of the transition.

Magnetization curves
====================

![$M$ vs $H_i$ for the compacted powder for temperature between 90 mK and 4.2 K. The internal field $H_i=H-NM$ was calculated with $N=1.68$ (cgs units) from $M$ vs $T$ measurements. []{data-label="fig_pwd_MH"}](Plot_YTOpwd_MH_Oe.pdf){width="7.0cm"}

The magnetization curves up to 80 kOe and down to 90 mK were performed for the compacted powder and with the field aligned along the \[100\] and \[110\] directions for the single crystal. Below 2 K, the magnetization is almost saturated above 60 kOe and reaches about 1.75 $\mu_B/$Yb.

Results for the compacted powder are shown in figure \[fig\_pwd\_MH\], where the field has been corrected for demagnetizating effects. We assumed that the demagnetizing factor is equal to the inverse value of the $M/H$ plateau at low temperature in figure \[fig\_MT\_HT\], that is to say $N=1.68$ (cgs units) (thus slightly below the estimated value from the sample shape).

Above 2 K, no clear anisotropy is observed. Below 1 K, the magnetization curves start to separate significantly. In particular, in the low field region, the magnetization increases much 