Figure 1

Magnetic tunnel junctions studied. Multilayered structure of MgO(001)//Cr (80)/Pd (5)/Co₂Fe_0.4Mn_0.6Si (30)/MgO (2)/Co_0.5Fe_0.5 (5)/IrMn₃ (10)/Ru (7)/Cr (5)/Au (80) (thickness in nm). The multilayers were patterned into magnetic tunnel junctions (MTJs) by photolithography and Ar-ion milling. MTJs were measured by a four-terminal method, showing a typical tunnelling magnetoresistance (TMR) ratio and resistance-area product (RA) of (a), 110% and 3.8 × 10⁴ Ω µm² and (b), 18% and 4.7 × 10³ Ω µm², respectively. In the supplementary section there are also results shown from a similar set of devices where CFMS = 5 nm.