**4. Conclusions**

The following are our conclusions, which are inferred based on the data obtained in simulating the magnetization reversal process of the (Nd1−<sup>х</sup>Ceх)2Fe14B compounds with х = 0–1.00 and their hysteresis loops in a wide temperature range of 300 to 0 K.

1. The model and algorithm developed for simulating the hysteresis loops of ferromagnets allow us to obtain important data on the effect of uniaxial tetragonal lattice, magnetic anisotropy parameters, and temperature dependences of the magnetic anisotropy constants on the characteristics of hysteresis loops (anisotropy field, residual magnetization, the shape of the hysteresis loop, and coercive force) in a wide temperature range.

2. Results of the simulation indicate that alloying of Nd2Fe14B with cerium to its contents *x* = 0.94 (1) does not lead to the complete elimination of the negative effect of spin-reorientation phase transition on the residual magnetization of the (Nd1−<sup>х</sup> Ceх)2Fe14B compounds and (2) slightly decreases the slope of the magnetization curve and almost does not lead to the improvement of the squareness of the back of hysteresis loop.

3. The alloying of (Nd1−<sup>х</sup>Ceх)2Fe14B with cerium to its contents *x* = 0.94 does not allow the temperature stability of hysteretic characteristics of (Nd1−<sup>х</sup>Ceх)2Fe14B-based permanent magnets to be increased in order to ensure their operation at low temperatures without losing magnetic properties.

**Author Contributions:** Conceptualization, N.B.K. and A.G.S.; methodology and calculations M.V.Z.; formal analysis, Y.S.K. and J.C.; data curation, V.P.M.; visualization, N.A.D.; writing—original draft preparation, N.B.K. ´ and M.V.Z.; writing—review and editing, N.B.K.; writing, K.S., M.K., and P.A.P.; project administration, G.S.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was supported by the Ministry of Science and Higher Education of the Russian Federation, agreemen<sup>t</sup> no. 05.604.21.0244, unique identification no RFMEFI60419X0244.

**Acknowledgments:** The authors thank Associate V.L. Stolyarov (National University of Science and Technology MISiS) for his assistance in the program Hysteresis.

**Conflicts of Interest:** The authors declare no conflict of interest.
