1. Full name: Truong Thanh Trung                                               2. Sex: Male

3. Date of birth: 26/11/1989                                                        4. Place of birth: Ha Noi

5. Admission decision number: Decision number 4982/QĐ-ĐHKHTN on 27/11/2013 by the Rector of VNU University of Science.

6. Changes in academic process: Extension decision No. 1033/QĐ-ĐHKHTN date on 25/4/2017 and Decision No. 597/QĐ-ĐHKHTN date on 06/3/2018, signed by the Rector of VNU University of Science;

7. Official thesis title: Synthesis and the role of structural transformation in magnetic properties of FePd and CoPt nanoparticles.

8. Major:                       Solid State Physics                               9. Code: 9440130.02

10. Supervisors:            Assoc.Prof.Dr. Nguyen Hoang Nam

                                    Prof.Dr.Sc. Nguyen Hoang Luong

11. Summary of the new findings of the thesis:

FexPd100-x (with x = 42, 50, 55, 60, 63) nanoparticles were prepared by sonoelectrodeposition.

- Under the influence of annealing temperature at various temperatures from 450oC to 700oC, observed structural transformation from disorder to order phase L10.

- After annealed at various temperatures the nanoparticles were found to have an ordered L10 structure and to show hard magnetic properties. The coercivity HC of sample shows highest value for x = 42, 50, 55, 63 samples annealed at 550°C, and at 600°C with x = 60.

- Fe60Pd40 sample shows highest coercivity. The coercivity of Fe60Pd40 sample annealed at 600°C shows highest value of 2.07 kOe at room temperature.

- The coercivity increases when decreasing temperature at all annealing temperature and have the highest value of 2.31 kOe measured at 2 K for Fe60Pd40 sample.

We have successfully prepared CoxPt100-x with x = 50, 59, 73 nanoparticles by chemical reduction combined with ultrasound.

-  Before annealed, as-prepared CoPt nanoparticles show disordered face centered cubic (fcc) structure. After annealed CoPt nanoparticles show order face centered tetragonal (fct) structures phase L10.

- Investigate the magnetic properties of CoPt nanoparticles which depend strongly on chemical composition and annealing temperature. Co50Pt50 sample shows highest coercivity. The highest coercivity value of 1.15 kOe was obtained at room temperature for Co50Pt50 sample annealed at 500oC.

- The coercivity increases when decreasing temperature at all annealing temperature and have the highest value of 1.6 kOe measured at 2 K for Co50Pt50 sample.

12. Practical applicability, if any: FePd and CoPt nanoparticles were successfully prepared by simple methods. FePd and CoPt nanoparticles with ordered L10 phase exhibit a large coercivity, they have attracted much interest as one of the candidates for future high-density magnetic storage media.

13. Further research directions, if any: Optimize nanoparticle fabrication process by changing factors in the fabrication process, such as: Change the intensity of ultrasound, the annealing time, investigate of the effects of surfactant…

14. Thesis-related publications:

1. Nguyen Hoang Luong, Truong Thanh Trung, Tran Phuong Loan, Luu Manh Kien, Tran Thi Hong, Nguyen Hoang Nam (2016), “Magnetic properties of FePd nanoparticles prepared by sonoelectrodeposition”, Journal of Electronic Materials 45(8), 4309–4313.

2. Truong Thanh Trung, Do Thi Nhung, Nguyen Hoang Nam, Nguyen Hoang Luong (2016), “Synthesis and magnetic properties of CoPt nanoparticles”, Journal of Electronic Materials 45(7), 3621-3623.

3. Truong Thanh Trung, Do Thi Nhung, Nguyen Thi Thanh Van, Nguyen Hoang Nam, Nguyen Hoang Luong (2016), “Magnetic properties of CoxPt100-x nanoparticles”, Journal of Science: Advanced Materials and Devices 1(1), 80-83.

4. Nguyen Hoang Luong, Truong Thanh Trung, Tran Phuong Loan, Nguyen Hoang Nam, Péter Jenei, János L. Lábár, Jenö Gubicza (2017), “Structure and Magnetic Properties of Nanocrystalline Fe55Pd45 Processed by Sonoelectrodeposition”, Journal of Electronic Materials 46(6), 3720–3725.