Separate magnetization switching of hexagonal Co/BN/Co junctions grown epitaxially on c-sapphire

TL;DR

This study demonstrates epitaxial growth of magnetic tunnel junctions with separate magnetization switching of Co layers, revealing potential for advanced spintronic devices with controlled magnetic states.

Contribution

First demonstration of epitaxial Co/BN/Co junctions with distinct switching behaviors of top and bottom Co layers grown in a single process.

Findings

Epitaxial growth of Co/BN/Co junctions achieved

Separate magnetization switching of Co layers observed

Antiparallel magnetic state at zero field detected

Abstract

Magnetic tunnel junctions (MTJ) have been grown by using molecular beam epitaxy on c-plane Al2O3 substrates. The MTJ stacks consist of two ferromagnetic hcp-Co layers separated by a thin insulating h-BN barrier. The samples have been grown in a single run revealing single crystalline epitaxial structures with sharp interfaces as observed by applying transmission electron microscopy. The in-plane magnetization experiments have revealed separate magnetization switching of a thin top Co (soft) layer and a thick bottom Co (hard) layer. At zero magnetic field the two Co layers are found in an antiparallel state.