Simulating the Hysteretic Characteristics of Hard Magnetic Materials Based on Nd2Fe14B and Ce2Fe14B Intermetallics

Abstract

The Ce2Fe14B intermetallic, like Nd2Fe14B, has the tetragonal Nd2Fe14B-type structure (space group P42/mnm), in which Ce ions have a mixed-valence state characterized by the coexistence of trivalent 4f1 and tetravalent 4f0 electron states. Despite the fact that the saturation magnetization, magnetic anisotropy field, and Curie temperature of the Ce2Fe14B intermetallic are substantially lower than those of Nd2Fe14B and Pr2Fe14B, Ce2Fe14B retains the capacity of being able to be used in the manufacturing of rare-earth permanent magnets. Moreover, at low temperatures, the anisotropy field of Се2Fe14B is higher than that of Nd2Fe14B, and Се2Fe14B does not undergo the spin-reorientation transition. In this respect, studies of (Nd, Ce)-Fe-B alloys, which are intended for the improvement of the service characteristics-to-cost ratio, are very relevant. A model and algorithm for calculating the hysteresis loops of uniaxial hard magnetic materials with allowance for the K1 and K2 (K2 > 0 and K1 > 0 and K1 < 0) magnetic anisotropy constants were developed and allowed us to obtain data on their effect on the parameters of hysteresis loops for a wide temperature range (0–300 K). The simulation and analysis of hysteresis loops of the quasi-ternary intermetallics (Nd1−хСех)2Fe14B (х = 0–1) was performed. Results of the simulation indicate that the alloying of the Nd2Fe14B intermetallic with Ce to x = 0.94 (1) does not completely eliminate the negative effect of spin-reorientation phase transition on the residual magnetization of the (Nd1−хCeх)2Fe14B intermetallic and (2) slightly decreases the slope of magnetization reversal curve.

Mechanochemical Synthesis and Nitrogenation of the Nd1.1Fe10CoTi Alloy for Permanent Magnet

“…For the µ 0 H c , a tendency to increase with the decrease in the temperature is shown in Figure 8; A maximum value of µ 0 H c = 1.259 T was obtained at 100 K. This fact indicates that the spin-reorientation transition occurs around this temperature, in agreement with the reported spin-reorientation temperature for the NdFe 11 TiH compound (100 K [27]). On the other hand, this change in the µ 0 H c with the decrease of the temperature was also observed in the (Nd 0.2 Ce 0.8 ) 2 Fe 14 B compound at 100 K, where it was similarly associated with the spin-reorientation temperature [31]. For the lower temperature of 50 K, the µ 0 H c decreases to 1.171 T as can be seen in Figure 8.…”