INVESTIGATION OF MATERIALS AND ANALYSIS TECHNIQUES FOR PERFORMANCE ENHANCEMENT OF PERPENDICULAR MAGNETIC TUNNEL JUNCTIONS

Perpendicular Magnetic tunnel junction (p-MTJ) is a promising candidate for future non-volatile memories. Some of the factors that are critical for the performance of p-MTJ are thermal stability, magnetic immunity against the external magnetic field and switching current (Ic). In this thesis, the issues of the thermal stability, and Ic of a double barrier p-MTJ free layer are studied by changing the composition of CoFeB free layer, along with the optimization of the material adjacent to magnetic free layer as perpendicular anisotropy enhancing layer (PEL). We find Co/(Co+Fe) ∼ 35% for the free layer and Ta/(W+Ta) ∼ 40% for the PEL to have highest anisotropy energy that enhances the thermal stability. In addition, Co/(Co+Fe) ∼ 35% is also found to have low Gilbert damping to improve switching current efficiency. Further, an improved method to predict bit error rate based on domain wall model for the magnetic immunity of the bit array is proposed.

Author dc:creator

• SRIVASTAVA SHALABH

• Magnetism, Magnetic anisotropy, Magnetic tunnel junctions, Thermal stability, Magnetic random access memory, Spintronics