Enhancing the interfacial perpendicular magnetic anisotropy and tunnel magnetoresistance by inserting an ultrathin LiF layer at an Fe/MgO interface
Takayuki Nozaki, Tomohiro Nozaki, Tatsuya Yamamoto, Makoto Konoto, Atsushi Sugihara, Kay Yakushiji, Hitoshi Kubota, Akio Fukushima, Shinji Yuasa
Abstract
Abstract Perpendicular magnetic anisotropy (PMA) is becoming increasingly important in spintronics research, especially for high-density magnetoresistive random access memories (MRAMs). The PMA induced at an Fe/MgO interface is widely used in magnetic tunnel junctions. Here, we propose inserting an ultrathin LiF layer at the interface in an epitaxial Fe/MgO junction. With a 0.3 nm-thick LiF layer, a large intrinsic interface PMA energy, K i ,0 , of 2.8 mJ/m 2 was achieved. We also found that the LiF/MgO bilayer tunneling barrier exhibited a large tunnel magnetoresistance (TMR) effect, suggesting that a coherent spin-dependent tunneling process was maintained in the ultrathin LiF layer. Atomic-scale interface engineering using fluoride can further improve the PMA and TMR properties of spintronic devices.