Electrical and magnetoresistive properties of the Ag/La2/3Sr1/3MnO3 point-probe contacts

I. Černiukė; B. Vengalis; A. Steikūnienė; G. Grigaliūnaitė-Vonsevičienė; A.K. Oginskis

doi:10.3952/physics.v55i1.3054

I. Černiukė
B. Vengalis
A. Steikūnienė
G. Grigaliūnaitė-Vonsevičienė
A.K. Oginskis

DOI: https://doi.org/10.3952/physics.v55i1.3054

Keywords: manganite films, magnetoresistance, 3 point-probe method, contact resistance, spreading resistance

Abstract

We report electrical and magnetoresistive properties of Ag point-probe contacts formed by attaching the bent Ag wire (∅ = 0.25 mm) to the top of the La_2/3Sr_1/3MnO₃ (LSMO) thin film magnetron sputtered at 800 °C on MgO(100) single crystal substrates. Significant contact magnetoresistance values (up to 13% at T = 295 K and μ₀H = 0.73 T) have been measured for the Ag/LSMO junctions by applying a 3 point-probe method. The origin of both temperature-dependent resistance and magnetoresistance of the Ag/LSMO contacts has been explained taking into account the dominating role of spreading resistance. It was found that keeping of the films in air for 1 month as well as ultrathin overlayers (d ~ 3–5 nm) of the highly resistive multiferroic BiFeO₃ magnetron sputtered onto the manganite film resulted in a significant increase of contact resistance and reduced magnetoresistance values.