Saturation magnetization and anisotropy fields in the Sm(Co1−xCux)5 phases

Abstract

The magnetic characteristics of high-anisotropy Sm(Co1−xCux)5 phases are determined experimentally at 300 K in the range x<0.6. The saturation magnetization Ms decreases and vanishes for SmCo2Cu3. Identical behaviors of Ms and Curie temperature TC versus x are observed in the range x<0.6. For significant Cu substitution rate (x≳0.35), the decrease of the anisotropy field (HA) when x increases is strong. For lower Cu contents, huge values of anisotropy fields make difficult the accurate determination of the substitution effect. The first anisotropy constant K1 is calculated using the available values of HA and Ms. A linear decrease of K1 is observed from SmCo5 to SmCo2Cu3.

Coercivity of Sm(Co0.9Cu0.1)4.8 melt-spun ribbons

“…Copper substituted SmCo 5 ribbons melt-spun at lower wheel surface speeds (5-10 m/s) were shown to exhibit a remenence of 9.5 kG and coercivity of 17 kOe [12]. It was reported that the partial substitution of copper in SmCo 5 alloys results in higher coercivity [13][14][15][16][17][18][19][20]. Recently Zhang et al have studied the effect of Cu substitution on structural and magnetic properties of anisotropic Sm-Co ribbons obtained at the wheel surface speed of 5 m/s [21].…”

Investigation of time dependent effects in the magnetization processes of Y Sm1−Co3Cu2 alloys

“…From their estimations they propose that, although the same fundamental magnetization process is investigated, both experiments probe energy barriers that differ by about 20%, because of different effective waiting times connected with the different methods. Experimentally, we have reported the values of S v of Nd 60 Fe 30 Al 10 and Nd 60 Fe 20 Co 10 Al 10 alloys determined from the analysis of magnetic relaxation at constant applied fields and the variation of the coercive field by changing the sweep rate [8]. We have found unequal S v values, that is, the viscosity coefficient determined from the decay of the coercive field with change in pulsed field rate (S vp ) can be up to 4 times larger than that (S vJ ) obtained from the magnetization relaxation experiments.…”

“…SmCo 5 is an important hard magnetic material, due to its large magnetic anisotropy energy, which comes mostly from the Sm-4f-shell anisotropy, stemming from an interplay between the crystal field and the spin-orbit coupling [9]. When substituting Cu for Co, for example, SmCo 3 Cu 2 , the saturation magnetization and the anisotropy field decrease with increasing Cu concentration [10] and the magnetization process changes from nucleation to pinning type, with an enhancement of the coercivity [4,5]. Contrary to the results of Sm(Co, Cu) 5 alloys, neither an enhancement of the coercivity nor a dH/dt dependence of the coercivity was visible in Y(Co, Cu) 5 alloys [11].…”

Investigation of cellular microstructure and enhanced coercivity in sputtered Sm2(CoCuFeZr)17 film

“…The Cu gradient from 1:5 cell phases to 2:17 cellular structure has a strong effect on the domain wall energy of the two phases due to different magnetocrystalline energy. 27 EDS analysis performed on a nonuniform cellular region of sample annealed at 700 C has shown that Cu is dominating in the cell boundary in the form of additional small precipitates and no significant gradient across the phase boundary has been observed. This suggests that the cell boundaries in the sample are acting as a non-uniform pinning source during the reversal magnetization process.…”