Rare-earth transition metal (RE-TM) alloy films and multilayers have been attracting increasing attention for their current applications in spintronics, ultrafast magnetism and magnonics. In the RE-TM alloys, the RE and TM sublattice magnetizations are antiferromagnetically coupled. Accordingly, there may exit a compensation point, where the moments of the RE and TM sublattices with opposite sign are equal in magnitude and the net magnetization is zero.

In this talk, we will present some results on magnetic and magnetoelectronic properties of sputtered amorphous ferrimagnetic RE-TM (Tb,Gd)FeCo alloy films and multilayers. A critical thickness is found in the ferrimagnetic alloy films, where both the lowest saturation magnetization and the largest coercivity are demonstrated. At this critical thickness the sign of the extraordinary Hall resistance is observed to change from positive for FeCo-rich films to negative for RE-rich films. An extraordinary Hall coefficient with one order larger than that in ferromagnetic [Co,CoFe/Pt] multilayers is obtained. Our results show ferrimagnetic RE-TM alloy films are useful for the applications in perpendicular spintronic devices.

References

1. K. Wang, L. Wu, Z. Xu, Z. H. Lu, R. Xiong, Extraordinary Hall effect of sputtered amorphous ferrimagnetic GdFeCo alloy films, Materials Today Communications 35 (2023) 10602.

2. K. Wang, J. Ma, J. Shi, X. P. Xiao, Y. L. Wang, J. J. Qi, J. Liu,Tuning perpendicular magnetic properties of sputtered rare-earth transition metal GdFeCo alloy films, Journal of Superconductivity and Novel Magnetism,34(9) (2021) 2455-2461.

3. K. Wang, Y. M. Tang, X. P. Xiao, Z. Xu, J. Liu, Fabrication of TbFeCo alloy films with tunable perpendicular coercivity evaluated by extraordinary Hall effect measurements, Journal of Materials Science 56 (2021) 4013–4021.

4. K. Wang, Y. H. Wang, J. Ma, Z. Xu, Sputtering fabrication of GdFeCo alloy films with perpendicular magnetic anisotropy, Vacuum, 163 (2019) 75–80.

Prof. Ke Wang obtained his BS and Ph.D degrees in microelectronics and solid state electronics from Huazhong University of Science and Technology. Currently, Prof. Wang is heading the School of Mechanical and Electronic Engineering in the East China University of Technology. Previously, he received Alexander von Humboldt (AvH) research award to work in RWTH-Aachen. Prof. Wang serves as Editorial Board Member for over ten scientific journals and as the Editor for publishing several international conference proceedings. He has published more than 80 peer reviewed papers and holds several patents. His expertise covers magnetic tin films and nanostructured spintronic devices.