title: Subtle Interplay between Localized Magnetic Moments and Itinerant Electrons in LaAlO3/SrTiO3 Heterostructures.
abstract: Clarification of the role of magnetic ordering and scattering in two-dimensional electron gas has become increasingly important to understand the transport and magnetic behavior in the LaAlO3 (LAO)/SrTiO3 (STO) heterostructures. In this work, we report the sheet resistance of the LAO/STO heterostructures as functions of temperature, magnetic field, and field orientation. An unexpected resistance minimum was discovered at ∼10 K under a sufficiently high in-plane magnetic field. An anisotropic magnetoresistance (MR) is clearly identified, indicating the presence of magnetic scattering which may be related to the interaction between itinerant electrons and localized magnetic moments in the LaAlO3/SrTiO3 heterostructures. It is believed that the high concentration of oxygen vacancies induced by the ultralow oxygen partial pressure during the deposition process plays a predominant role in the occurrence of the anisotropic MR.
authors.affiliation: School of Materials Science & Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Hai-Long
authors.initials: HL
authors.lastname: Hu
authors.affiliation: School of Materials Science & Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Rong
authors.initials: R
authors.lastname: Zeng
authors.affiliation: School of Materials Science & Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Anh
authors.initials: A
authors.lastname: Pham
authors.affiliation: School of Materials Science & Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Thiam Teck
authors.initials: TT
authors.lastname: Tan
authors.affiliation: School of Mechanical & Mining Engineering, The University of Queensland , Brisbane, Queensland 4072, Australia.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Mark Wainwright Analytical Centre, The University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Charlie
authors.initials: C
authors.lastname: Kong
authors.affiliation: School of Materials Science & Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Danyang
authors.initials: D
authors.lastname: Wang
authors.affiliation: School of Materials Science & Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Sean
authors.initials: S
authors.lastname: Li
keywords: LaAlO3/SrTiO3 heterostructures; anisotropic magnetoresistance; itinerant electrons; localized magnetic moments; oxygen vacancy