Hard magnetic properties in isotropic nanocomposite Pr2Fe14B/α-Fe ribbons

Investigation on magnetic properties of orientated nanocomposite Pr2Fe14B/α-Fe permanent magnets by micromagnetic finite-element method

“…The calculated results show that the demagnetization curves show a single-phase behavior for d¼10 nm and a two-phase behavior for d 410 nm, which is coincide with the experimental results [25,26]. It is suggested that more information on magnetization reverse can be obtained from the plot of w total versus H for two-phase behavior magnets [27]. Fig.…”

The intergrain exchange coupling in Sm(Co,Fe,Cu,Zr)z magnets with z = 7.0 and 7.5

“…Here the remanent J r (H ) can be obtained after applying and subsequent removal of a direct field H , J d (H ) after saturation and the subsequent application and removal of a direct field H in the reverse direction, and J r (∞) is the saturated remanent and denoted as J r in the following for convenience. It is well known that the positive value of δ m (H ) is due to IGEC, while the negative value of δ m (H ) is the result of dipole-dipole coupling [21,[25][26][27][28][29]. Figure 6 shows δ m versus H (Henkel plot) at different temperatures.…”

“…As shown in figure 5, the recoil loops do not close for both samples. According to the reports on nanocomposite PMs in [21,23,24], such a behaviour is attributed to the effect of the stray field on the irreversible behaviour of the soft phase when the cell boundary phase is considered to be magnetically soft. Recently, the coercivity mechanism was found to be controlled mainly by the pinning of domain walls in the modern Sm(Co,Fe,Cu,Zr) z PMs, but also in the traditional ones when the temperature is below the Curie temperature of the cell boundary phase.…”

“…Obviously, the domains size of both A and B samples are much larger than their grains size according to the results of analysis by the Scherrer method from XRD. The magnetic structure is so called multigrain domains or interaction domains also found in other nanocrystalline PM ribbons and nanocomposite ribbons [7,20,21]. The interaction domains are considered as the result of exchange interactions between the spins of adjacent grains.…”

Investigation on the coercivity and remanence of single-phase nanocrystalline permanent magnets by micromagnetic finite-element method

“…13 shows the temperature dependence of reduced remanence m r : Except the values of m r for x 4 ¼ 0:5 and x 5 ¼ 2 at 350 and 400 K, m r decreases with the drop of temperatures, which is consistent with the experimental results in Refs. [28,29]. For x 4 ¼ 2 and x 5 ¼ 0:5; m r is smaller than that for x 4 ¼ x 5 ¼ 1 at the same temperature, while the highest m r is obtained for x 4 ¼ 0:5 and x 5 ¼ 2: Enhancing exchange coupling is of benefit to get high m r : On the contrary, m r decreases with enhancement of anisotropy.…”