Effect of A Cr Underlayer on the Magnetic Properties of TbCoAmorphous Films with Perpendicular Anisotropy

The effect of the Cr underlayer on the magnetic properties of TbCo amorphous films with perpendicular anisotropy has been investigated. It was found that the Cr underlayer thickness can influence the coercivity of TbCo films. The coercivity as high as 6.3 kOe was obtained in 120 nm Tb₃₁Co₆₉ films with 180 nm Cr underlayer. It was only 4.4 kOe for the same thickness Tb₃₁Co₆₉ films without the Cr underlayer. Cross-sectional scanning electron microscopy indicated that the TbCo film with the Cr underlayer consisted of the column structure. It is considered that this heterogeneous structure gives rise to the coercivity enhancement of TbCo films in the presence of the Cr underlayer.