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Title: Voltage-controlled ferromagnetism and magnetoresistance in LaCoO{sub 3}/SrTiO{sub 3} heterostructures

A LaCoO{sub 3}/SrTiO{sub 3} heterostructure grown on Si (001) is shown to provide electrically switchable ferromagnetism, a large, electrically tunable magnetoresistance, and a vehicle for achieving and probing electrical control over ferromagnetic behavior at submicron dimensions. Fabrication of devices in a field-effect transistor geometry enables application of a gate bias voltage that modulates strain in the heterostructure via the converse piezoelectric effect in SrTiO{sub 3}, leading to an artificial inverse magnetoelectric effect arising from the dependence of ferromagnetism in the LaCoO{sub 3} layer on strain. Below the Curie temperature of the LaCoO{sub 3} layer, this effect leads to modulation of resistance in LaCoO{sub 3} as large as 100%, and magnetoresistance as high as 80%, both of which arise from carrier scattering at ferromagnetic-nonmagnetic interfaces in LaCoO{sub 3}. Finite-element numerical modeling of electric field distributions is used to explain the dependence of carrier transport behavior on gate contact geometry, and a Valet-Fert transport model enables determination of spin polarization in the LaCoO{sub 3} layer. Piezoresponse force microscopy is used to confirm the existence of piezoelectric response in SrTiO{sub 3} grown on Si (001). It is also shown that this structure offers the possibility of achieving exclusive-NOR logic functionality within a singlemore » device.« less
Authors:
; ;  [1] ; ;  [2] ;  [3]
  1. Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States)
  2. Department of Physics, The University of Texas at Austin, 1 University Station C1600, Austin, Texas 78712 (United States)
  3. IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States)
Publication Date:
OSTI Identifier:
22217869
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 18; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ATOMIC FORCE MICROSCOPY; CARRIERS; CURIE POINT; EQUIPMENT; FABRICATION; FERROMAGNETIC MATERIALS; FERROMAGNETISM; FIELD EFFECT TRANSISTORS; FINITE ELEMENT METHOD; LANTHANUM COMPOUNDS; LEAD; MAGNETIC PROPERTIES; MAGNETORESISTANCE; MOLECULAR BEAM EPITAXY; PIEZOELECTRICITY; SCATTERING; SPIN ORIENTATION; STRAINS; STRONTIUM TITANATES; THIN FILMS