Eur. Phys. J. B 48, 37-40 (2005)
https://doi.org/10.1140/epjb/e2005-00371-4

Magnetotransport properties of nano-constriction array in La_0.67Sr_0.33MnO₃ film

¹ Centre for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
² Data Storage Institute, 5 Engineering Drive 1, DSI Building, Singapore 117608, Singapore

Corresponding author: ^a g0306128@nus.edu.sg

Received: 14 May 2005
Published online: 9 December 2005

Abstract

Nano-constriction array in La_0.67Sr_0.33MnO₃ film was fabricated by using ion beam etching masked by a monolayer of packed and ordered array of SiO₂ microspheres. Nano-constrictions of around 50 nm in width were fabricated. The low field magnetoresistance (LFMR) exhibited in the samples were observed to be current dependent and the I-V characteristics of the film were found to be nonlinear. These observations were attributed to the co-existence of the ferromagnetic regions and the nano-constricted region of weakened ferromagnetic coupling where Mn³⁺-O-Mn⁴⁺ bond were distorted due to the ion beam bombardment. The spin polarized bias current would strengthen local ferromagnetic coupling when passing through this nano-constricted regions. This current effect is relatively large comparing to the external magnetic field to the drop of resistance.