Tunnelling magnetoresistance of the half-metallic compensated ferrimagnet Mn2RuxGa

• Published in: Applied physics letters 2016-05, Vol.108 (19)
• Main Authors: Borisov, K, Betto, D, Y-C, Lau, Fowley, C, Titova, A, Thiyagarajah, N, Atcheson, G, Lindner, J, Deac, A M, Coey J M D, Stamenov, P, Rode, K
• Format: Article
• Language: English
• Subjects: Applied physics; Compensation; Computer memory; Ferrimagnetism; Immunity; Lattices; Magnetic anisotropy; Magnetic moments; Magnetism; Magnetoresistance; Magnetoresistivity; Oscillators; Polarization (spin alignment); Random access memory; Tunnel junctions; Tunnel magnetoresistance
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4948934

Tunnel magnetoresistance ratios of up to 40% are measured between 10 K and 300 K when the highly spin-polarized compensated ferrimagnet, Mn2RuxGa, is integrated into MgO-based perpendicular magnetic tunnel junctions. Temperature and bias dependences of the tunnel magnetoresistance effect, with a sign change near −0.2 V, reflect the structure of the Mn2RuxGa interface density of states. Despite magnetic moment vanishing at a compensation temperature of 200 K for x≈0.8, the tunnel magnetoresistance ratio remains non-zero throughout the compensation region, demonstrating that the spin-transport is governed by one of the Mn sub-lattices only. Broad temperature range magnetic field immunity of at least 0.5 T is demonstrated in the same sample. The high spin polarization and perpendicular magnetic anisotropy make Mn2RuxGa suitable for applications in both non-volatile magnetic random access memory cells and terahertz spin-transfer oscillators.