Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 19: Poster 1

MA 19.58: Poster

Tuesday, September 6, 2022, 17:30–20:00, P2

Ti , V, Ta, Nb as a boron sink in crystalline CoFeB/ MgO/ CoFeB Magnetic Tunnel Junctions — •Tobias Peters, Laila Bondzio, Inga Ennen, and Günter Reiss — Center for Spinelectronic Materials and Devices, University of Bielefeld, Germany

We investigated the tunnel magnetoresistance (TMR) in CoFeB/MgO/ CoFeB Magnetic Tunnel Junctions (MTJs) and studied the use of Ti, V, Ta and Nb as a boron getter during thermal annealing. Exchange bias MTJs were deposited by sputtering deposition. The basic TMR stack was modified by inserting an additional ultrathin layer into the CoFeB bottom electrode and changing the capping layer with the stated materials. TMR measurements have been performed for samples post-annealed at temperatures from 270°C to 420°C for 1h. The boron diffusion was observed via Electron Energy Loss Spectroscopy and Transmission Electron Microscopy. Nb-samples show the highest TMR for post-annealing temperatures smaller then 360°C. For higher temperatures we found even higher TMR for a Ta-sample. However, the insertion of Ta in the CoFeB electrode leads to a severe loss of pinning.