We investigated the composition dependence of the microstructure and magnetic properties of Co90Fe10-Zr film and the thermal and structural stability of MTJs with CoFeZr layers. As the Zr concentration in the Co90Fe10-Zr film increased, the grain size decreased rapidly, and the alloy films became a homogeneous amorphous phase when the concentration of Zr exceeded 15 at%. The TMR ratio of the MTJs with Co90Fe10 layers decreased when the samples were annealed at a temperature above 300 °C, whereas that of the MTJs with amorphous CoFeZr layers only started to decrease when they were annealed at a temperature above 350 °C. The MTJs with CoFeZr layers retained a significant TMR value of 28%, even after annealing at 450 °C. The enhanced structural quality of the interfaces improved the thermal stability of the MTJs with amorphous CoFeZr layers.
Bibliographical noteFunding Information:
This work was supported by grants from the Korea Research Foundation (KRF-2004-005-C00068) and the Basic Research Program of the KOSEF (R-01-2005-000-11188-0).
- Amorphous CoFeZr
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics