[9p-S1-1~7] State-of-the-art spintronics using layered materials

3:45 PM - 4:15 PM JST(6:45 AM - 7:15 AM UTC)

[9p-S1-5] Theory for tunnel magnetoresistance in junctions with two-dimensional insulators

〇Keisuke Masuda¹, Ivan Kurniawan¹, Yoshio Miura^1,2 (1.NIMS, 2.KIT)

Keywords:

hexagonal boron nitride (h-BN),tunnel magnetoresistance (TMR),magnetic tunnel junction (MTJ)

We theoretically studied the tunnel magnetoresistance (TMR) effect in magnetic tunnel junctions (MTJs) with hexagonal boron nitride (h-BN) barriers. Our analysis combining the first-principles calculation and the Landauer theory obtained a high TMR ratio of ~500% in an hcp-Co/h-BN/hcp-Co(0001) MTJ. The TMR ratio was further enhanced by substituting Ni for Co in the hcp-Co electrodes. We show that these high TMR ratios originate from resonant tunneling of surface states in the ferromagnetic electrodes. This mechanism is different from the Δ₁ coherent tunneling based on the bulk electronic states and the resonance tunneling of interfacial electronic states.