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Title: LaAlO{sub 3} thickness window for electronically controlled magnetism at LaAlO{sub 3}/SrTiO{sub 3} heterointerfaces

Complex-oxide heterostructures exhibit rich physical behavior such as emergent conductivity, superconductivity, and magnetism that are intriguing for scientific reasons as well as for potential technological applications. It was recently discovered that in-plane magnetism at the LaAlO{sub 3}/SrTiO{sub 3} (LAO/STO) interface can be electronically controlled at room temperature. Here, we employ magnetic force microscopy to investigate electronically controlled ferromagnetism at the LAO/STO interface with LAO thickness t varied from 4 unit cell (u.c.) to 40 u.c. Magnetic signatures are observed only within a thickness window 8 u.c. ≤ t ≤ 25 u.c. Within this window, the device capacitance corresponds well to the expected geometric value, while for thicknesses outside this window, the capacitance is strongly suppressed. The ability to modulate electronic and magnetic properties of LAO/STO devices depends on the ability to control carrier density, which is in turn constrained by intrinsic tunneling mechanisms.
Authors:
; ; ;  [1] ;  [2] ; ;  [3]
  1. Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)
  2. (United States)
  3. Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
Publication Date:
OSTI Identifier:
22489161
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 8; 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; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINATES; ATOMIC FORCE MICROSCOPY; CAPACITANCE; CARRIER DENSITY; FERROMAGNETISM; LANTHANUM OXIDES; MAGNETIC FIELDS; MAGNETIC PROPERTIES; STRONTIUM TITANATES; SUPERCONDUCTIVITY; TEMPERATURE RANGE 0273-0400 K; THICKNESS; TUNNEL EFFECT