Magnetic hardening of mechanically alloyed Pr2Co7

Magnetic hardening of mechanically alloyed Pr2Co7 Proceedings Paper

Bessais, L, Fersi, R, Cabié, M et al. (2012). Magnetic hardening of mechanically alloyed Pr2Co7 . 1471 12-17. 10.1557/opl.2012.1075

The PT2Co7 alloys are known to crystallize in two polymorphic forms: a hexagonal of the Ce2Ni7 type structure and a rhombohedral of the Gd2Co7 one. They were synthesized by mechanical milling and subsequent annealing in high vacuum. In this work, we focus on the structural study of these phases using X-ray diffraction and transmission electron microscopy. Also, we present the evolution of magnetic properties of these compounds vs the annealing temperature. The coercivity increases with annealing temperature reaching a maximum for T A = 800 °C. The highest is equal to 18 kOe at 293 K and 23 kOe at 10 K. The high magnetic properties observed in these nanostructured Pr 2Co7 intermetallic alloys have their origin in its relatively high uniaxial magnetocrystalline anisotropy field, and in the homogeneous nanostructure developed by mechanical milling process and subsequent annealing. This high coercivity is attributed to the high anisotropy field of the Pr2Co7 phase and its nanoscale grain size. This leads to the formation of a magnetically hard PT2CO7 phase. © 2012 Materials Research Society.