2023/08/08 by Jieyuan Song, Thomas Scheike, Song, Jieyuan +13
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Heusler alloys: electronic and magnetic properties #Magnetic and transport properties of perovskites and related materials #Magnetic properties of thin films #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2308.04149
openalex publication_date 2023/08/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Magnetic tunnel junctions (MTJs) with bcc(001)-type structures such as Fe(001)/MgO(001)/Fe(001), have been widely used as the core of various spintronic devices such as magnetoresistive memories; however, the limited material selection of (001)-type MTJs hinders the further development of spintronic devices. Here, as an alternative to the (001)-type MTJs, an fcc(111)-type MTJ using a fully epitaxial CoFe/rock-salt MgAlO (MAO)/CoFe is explored to introduce close-packed lattice systems into MTJs. Using an atomically flat Ru(0001) epitaxial buffer layer, fcc(111) epitaxial growth of the CoFe/MAO/CoFe trilayer is achieved. Sharp CoFe(111)/MAO(111) interfaces are confirmed due to the introduction of periodic dislocations by forming a 5:6 in-plane lattice matching structure. The fabricated (111) MTJ exhibits a tunnel magnetoresistance ratio of 37% at room temperature (47% at 10 K). Symmetric differential conductance curves with respect to bias polarity are observed, indicating the achievement of nearly identical upper and lower MAO interface qualities. Despite the charge-uncompensated (111) orientation for a rock-salt-like MAO barrier, the achievement of flat, stable, and spin-polarized barrier interfaces opens a promising avenue for expanding the design of MTJ structures.