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Title: Geometric tuning of charge and spin correlations in manganite superlattices

We report a modulation of the in-plane magnetotransport in artificial manganite superlattice [(NdMnO{sub 3}){sub n}/(SrMnO{sub 3}){sub n}/(LaMnO{sub 3}){sub n}]{sub m} by varying the layer thickness n while keeping the total thickness of the structure constant. Charge transport in these heterostructures is confined to the interfaces and occurs via variable range hopping. Upon increasing n, the interfacial separation rises, leading to a suppression of the electrostatic screening between carriers of neighboring interfaces and the opening of a Coulomb gap at the Fermi level (E{sub F}). The high-field magnetoresistance (MR) is universally negative due to progressive spin alignment. However, at a critical thickness of n = 5 unit cells (u.c.), an exchange field coupling between ferromagnetically ordered interfaces results in positive MR at low magnetic field (H). Our results demonstrate the ability to geometrically tune the electrical transport between regimes dominated by either charge or spin correlations.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ; ;  [4] ;  [1] ;  [2] ;  [5] ;  [2]
  1. Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Vassilika Vouton, Heraklion 71110 (Greece)
  2. (Greece)
  3. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
  4. School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)
  5. (Singapore)
Publication Date:
OSTI Identifier:
22399132
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHARGE CARRIERS; CHARGE TRANSPORT; CORRELATIONS; COUPLING; FERMI LEVEL; INTERFACES; LANTHANUM COMPOUNDS; MAGNETIC FIELDS; MAGNETORESISTANCE; MANGANATES; MODULATION; NEODYMIUM COMPOUNDS; SPIN; STRONTIUM COMPOUNDS; SUPERLATTICES; THICKNESS