Effect of annealing on structural and magnetic properties of Pr2Co7 compounds

Impact of carbon insertion on the microstructure and magnetic properties of nanocrystalline Pr2Co7 alloys

“…Previous study [8] has shown that at an annealing temperature (T a ) less than 1023 K, the Pr 2 Co 7 compound can exist in a hexagonal Ce 2 Ni 7 -type structure with P6 3 /mmc space group, the lattice parameters were a = b = 5.068 Å and c = 24.463 Å and the Pr atoms occupy two crystallographic 4f sites while cobalt atoms occupy 12k, 6h, 4f, 4e and 2a sites.…”

“…They might crystallize in a hexagonal structure of the Ce 2 Ni 7 type, stable at low temperature ðT < 1023 KÞ or a rhombohedral one of the Gd 2 Co 7 type structure, stable at high temperatures ðT > 1223 KÞ [8,9]. The Pr 2 Co 7 alloys present interesting magnetic properties such as large magnetocrystalline anisotropy and important saturation magnetization [10].…”

“…The Pr 2 Co 7 alloys present interesting magnetic properties such as large magnetocrystalline anisotropy and important saturation magnetization [10]. The Curie temperature of the Pr 2 Co 7 compound is around 600 K for hexagonal structure and 580 K for rhombohedral one [8,11]. Therefore, chemical variations, which would enhance the Curie temperature, are of permanent interest.…”

Intrinsic and extrinsic magnetic properties of nanocrystalline Pr2(Co,Fe)7

“…3 Results and discussion 3.1 Structural and microstructural studies As was mentioned above, the Pr 2 Co 7 intermetallic compounds can crystallize in two structures [3] depending on annealing temperature: a hexagonal of the Ce 2 Ni 7 -type structure (P6 3 / mmc space group), stable at low temperature (T 1023 K), having lattice parameters a ¼ b ¼ 5.068 Å and c ¼ 24.463 Å. The Pr atoms occupy two crystallographic 4f sites while cobalt atoms occupy 12k, 6h, 4f, 4e, and 2a sites.…”

“…This leads to the formation of a magnetically hard Pr 2 Co 7 phase; the coercivity (H c ) being equal to 18 kOe at room temperature and 23 kOe at 10 K with an important saturation magnetization M s [3]. These effects are due to the combination of the complementary characteristics of 3d-itinerant and 4f-localized magnetism of Co and R atoms, respectively [4].…”