Study of interface and its role in an unusual magnetization reversal in 57FeCoB/MgO bilayer

Autor: Md. Shahid Jamal, Pooja Gupta, Dileep Kumar, Ilya Sergeev, Hans-Christian Wille, Mukul Gupta, Yogesh Kumar
Rok vydání: 2021
Předmět:
Zdroj: Hyperfine Interactions. 242
ISSN: 1572-9540
0304-3843
Popis: FeCoB/MgO bilayer is prepared to study the interface magnetism and its role in azimuthal angle-dependent magnetic properties. As observed in magneto-optic Kerr effect measurements, unusual hysteresis loops are understood precisely through interface resolved grazing incident nuclear resonance scattering (GINRS) measurements under x-ray standing wave (XSW) conditions. To excite XSW modes, the bilayer is deposited between a Pt waveguide structure, where the position of the anti-nodes is varied by changing incident angles. As GINRS is an isotope sensitive technique, the FeCoB layer is enriched with 57Fe isotope during deposition. The formation of a high-density 57FeCoB layer at the 57FeCoB/MgO interface with a hyperfine field ~34.25 T is found and attributed to the increasing volume of FeCo at the interface. Boron diffusion from 57FeCoB to the MgO layer is found to be responsible for FeCo rich FeCoB layer near the interface. The azimuthal angle-dependent unusual shape of hysteresis loops is described in terms of coupled magnetization reversal between the bulk and interface parts of FeCoB layer. In contrast to some studies in literature, no evidence of the formation of an oxide layer is observed at the interface.
Databáze: OpenAIRE
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