2024/06/12 by Masuda, Keisuke, Scheike, Thomas, Sukegawa, Hiroaki +3
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.2406.07919
The universal oscillation of the tunnel magnetoresistance (TMR) ratio as a function of the insulating barrier thickness in crystalline magnetic tunnel junctions (MTJs) is a long-standing unsolved problem in condensed matter physics. To explain this, we here introduce a superposition of wave functions with opposite spins and different Fermi momenta, based on the fact that spin-flip scattering near the interface provides a hybridization between majority- and minority-spin states. In a typical Fe/MgO/Fe MTJ, we solve the tunneling problem and show that the TMR ratio oscillates with a period of ∼3 Å by varying the MgO thickness, consistent with previous and present experimental observations.