Structural stability and magnetic properties of SmCo7−xGax

Abstract

We have studied the structural stability and magnetic properties of SmCo7−xGax compounds using powder x-ray diffraction and magnetic measurements. Gallium as a dopant not only stabilizes the SmCo 1:7 phase but also induces a strong uniaxial magnetocrystalline anisotropy. An anisotropy field as high as 30.7 T is observed at 5 K in the SmCo6Ga compound. The strong anisotropy field might be due to the occupation of Ga atom. The structural stability of SmCo7−xGax compounds is related to the effective Sm/(Co,Ga) atomic radius ratio (RA) and the difference in electronegativity (XA) between Sm and (Co,Ga). According to our calculation, the SmCo 1:7 type structure can be stabilized in range from 1.08(5) to 1.12(9) for RA and −1.04(4) to −0.94(4) for XA.