Xiang-Dong Jiang

The structure and soft magnetic properties of rapid recurrent thermal annealing CoNbZr nanocrystalline alloys thin films

Abstract Soft magnetic thin film and devices, especially nanometer crystal soft magnetic thin film, are touching in peoples attention with good quality and widely application. We have developed a new method to use to nanocrystallize the amorphous CoNbZr thin film fabricated by DC magnetic sputtering under different conditions. The grain size of this film can be fined to 20–30 nm, the structure and properties of nanometer crystal thin film obviously be improved as controlling the temperature duration and recurrent times. The permeability increase from 3500 to over 5000, coercivity decrease from 4.6 to 1.5 Oe, resistivity from 1.4 to 0.5 Ωcm. The great improvement of soft magnetic film properties has obtained.

Theoretical and experimental investigation on giant magnetoresistive materials with amorphous ferromagnetic layer

Abstract Pseudo-spin-valve (PSV) sandwiches using amorphous CoNbZr alloy as soft magnetic layer were fabricated by magnetron sputtering. The giant magnetoresistance (GMR) and its dependence on the thickness of magnetic layer were investigated. Anti-parallel magnetization alignments were observed in the samples with very thin CoNbZr thickness (2–4 nm) and a maximum GMR ratio of 6.5% was obtained. The Camley-Barnas semiclassical model was extended for amorphous layer based magnetic sandwiches by considering that the mixed layers exist between the ferromagnetic and nonmagnetic layer. The calculated results agree with the experimental results very well, indicating that the new model gives a more realistic picture of the physical processes that take place in the magnetic sandwiches. Moreover, the calculated results for amorphous sandwiches also clarify that the occurrence of maximum GMR at very small thickness of amorphous layer is ascribed to the short mean-free-path in amorphous materials.

Magnetoresistance and performance of amorphous-CoNbZr∕Co∕Cu∕Co magnetic multilayers

A pseudo spin-valve (PSV) using amorphous CoNbZr alloy as a soft magnetic layer and buffer layer was proposed. The giant magnetoresistance (GMR), thermal annealing effect, and the performance were investigated. Antiparallel magnetization alignments were observed in the samples with 2–4nm CoNbZr layer and a maximum GMR of 6.5% was obtained. Furthermore, sandwich with relatively thick CoNbZr layer has a superior thermal stability to 400°C and a GMR enhancement to about 9%. After patterning to 6μm×1μm elliptic stripe, a single domain forms and the dynamic MR behavior indicates the stripe has a linear and stable GMR response. Therefore, it is believed that the PSVs with amorphous CoNbZr layers have good potentials for spin-electronic devices.

The influence of rapid recurrent thermal annealing on magnetic properties of CoFe-O thin film

The variation of magnetic properties with a new rapid recurrent thermal annealing (RRTA) were studied in high moment thin film (Co 0.35Fe0.65)99O1. After the rapid recurrent thermal annealing at 450°C for several periods of times, the coercivity as-deposited this thin film decreased from 105 to 3 Oe, and their resistivity was decreased to 70 percent. It is found that the method is more effective than other methods to improve the magnetic and electrical properties of (Co0.35Fe0.65)99O1 thin films.