School of Physical and Chemical Sciences Te Kura Matū Seminar Series

Effect of Magnetic Impurities on Magneto-transport Properties of Strongly Correlated Transitional Metal Oxide Thin Films

Speaker

Susant Kumar Acharya

Institute

Department of Physical and Chemical Sciences, University of Canterbury

Time & Place

Fri, 03 Aug 2018 11:00:00 NZST in Room 531, Level 5, West Building (formerly known as the Rutherford Building)

All are welcome

Abstract

Strongly correlated transition metal oxides having a perovskite structure display a wide range of physical phenomena including high magnetoresistance (MR) and high-temperature superconductivity. These materials are associated with several competing ground states due to the existence of different degrees of freedom, such as the spin, orbital, and lattice deformations. Such systems are often easily perturbed by magnetic field, pressure, or chemical substitution. Among the numerous correlated materials, SrRuO3 (SRO) based on the 4d element Ru4+has been the center of attention in this research field for the last few decades due to the rich variety of its properties. The transport and magnetic properties of SRO can be significantly modified by chemical substitution at both the Sr and Ru sites.

In this talk, I will present our work on effect of A-site and B-site doping in SRO thin films. For this purpose, highly epitaxial SRO thin films were grown by pulse laser deposition (PLD) on SrTiO3 (001) substrate and we introduced varying concentration of La and Fe impurities on A-site and B-site of SRO, respectively. The resistivity increased and the ferromagnetic transition temperature TC decreased with an increase in magnetic impurity doping. At higher magnetic impurity doping, we could see a clear metal-to-insulator phase transition at low temperature and we also observed a well-defined resistivity minimum. The upturn in the resistivity curve is associated with the large electron-electron interaction due to introduction of magnetic impurity. The magnetoresistance values increased with increase in magnetic impurity, and we observed a large negative magnetoresistance at higher magnetic impurity doping. The observed high MR values are associated with spin fluctuation of the mobile electronic carriers in the material.

References:

  1. G. Koster, L. Klein, W. Siemons, G. Rijnders, J. S. Dodge, C-B. Eom, D. H. A. Blank, M, R. Beasley, Rev. Mod. Phys. 84, 253 (2012)
  2. K. R. N. Toreh, D.-H. Kim, U. Dash, T.-L. Phan, B. W. Lee, H.-W. Jin, S. Lee, B. H. Park, J.-Y. Park, M. R. Cho, Y. D. Park, S. K. Acharya, M. H. Jung, C. U. Jung, J. Alloys Compd. 657, 224 (2016) 
  3. U. Dash, S. K. Acharya, B. W. Lee, C. U. Jung, Nanoscale Res. Lett. 12, 168 (2017).
  4. U. Dash, S. K. Acharya, S.W Cho, S. Lee, K. Lee, S. C. Chae, M. R. Cho, C. U. Jung J. Alloys Compd. 724, 549 (2017)

Biography

Susant Kumar Acharya is a Research Fellow working with Simon Brown's nanotechnology group - http://www.canterbury.ac.nz/science/schools-and-departments/phys-chem/research/nano/