Composition and annealing dependence of magnetic properties in amorphous Tb–Co based alloys

Magnetic properties in some sputtered RCo2 amorphous alloys (R = rare-earth = Er, Sm, Tb)

“…Samples with x < 0.62 were found to order ferromagnetically below 300 K. The results give a very high ordering temperature T c up to 600 K for x > 0.68, as an example for Tb 1−x Co x samples [3]. The obtained values are in good agreement with those found by other authors [7].…”

“…4b): this can be explained by the competition which occurs between a well-defined in-plane anisotropy and a perpendicular anisotropy. This is a biaxial anisotropy regime where there are competing in-plane and perpendicular anisotropy terms [3,10]. The change of magnetisation by annealing the Er-Co amorphous alloy, under applied field (about 2 T, 300 • C), modifies the loop, resulting in a strongly modified loop area with a weak decrease of a coercive force H C and of M R (Fig.…”

“…Thus, it is interesting to remind that T c in the crystalline state of RCo 2 alloys are below the room temperature; contrary to an amorphous state, the results give very high ordering temperatures, T c up to 600 K for x > 0.68, as an example for Tb 1−x Co x samples [3]. This was explained in terms of band narrowing in the amorphous state which renders the Co-sublattice strongly magnetic at room temperature having a well-defined ferromagnetic coupling of the Co moments [7].…”

“…The magnetic structure of the rare-earth transition-metal amorphous alloys have been intensively studied in earlier works [1][2][3]. Among all researched properties, the magnetization and the shape of hysteresis loops are dependent upon the alloy composition, heat and mechanical treatment.…”

“…As an example, critical cobalt content for magnetic disappearance in amorphous is greater than in crystallized. This value, x = 0.8 for Tb 1−x Co x , is the compensation point, which corresponds to a vanishing of spontaneous magnetization [3,6].…”