An ordered stack of spin valves in a layered magnetoresistive perovskite

Abstract

The layered compound La2-2xSr1+2xMn2O7 (x=0.3) consists of bilayers of metallic MnO2 sheets separated by insulating material. The compound exhibits markedly anisotropic magnetoresistance at temperatures well below the three-dimensional magnetic ordering temperature TC=90 K in addition to colossal magnetoresistance around TC. We present neutron diffraction data which show that the magnetic structure of this material switches from antiferromagnetic stacking of the (ferromagnetically ordered) sheets in zero field to ferromagnetic stacking in a field of 1.5 Tesla. The data are the first to be collected on any manganite as a function of applied field, exactly as the magnetoresistance data themselves are collected. They provide a natural explanation of the low-field magnetoresistance in the ordered phase in terms of spin-polarised tunnelling between the magnetic layers and suggest that the material is a bulk stack of spin-valve devices.

11 pages and 3 figures To be published in Phys. Rev. B Rapid Communications

References in corpus (2)

• Electronic Raman scattering and photoluminescence from La${}_{0.7}$Sr${}_{0.3}$MnO${}_3$ exhibiting giant magnetoresistance
• Neutron scattering investigation of magnetic bilayer correlations in $L{a}_{1.2}S{r}_{1.8}M{n}_2{O}_7$

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• Charge Ordering and Phase Competition in the Layered Perovskite Lasr2mn2o7
• Polarons and confinement of electronic motion to two dimensions in a layered transition metal oxide
• Spin-valve effect and magnetoresistivity in single crystalline Ca3Ru2O7
• Ruthenocuprates RuSr2(Eu,Ce)2Cu2O10: Intrinsic magnetic multilayers
• Spectacular doping dependence of interlayer exchange and other results on spin waves in bilayer manganites
• Direct Imaging of the First Order Spin Flop Transition in the Layered Manganite La1.4Sr1.6Mn2O7
• Spin and orbital ordering in double-layered manganites
• Spin, Orbital and Charge Order at the Interface between Correlated Oxides
• Intrinsic Tunneling in Cuprates and Manganites
• Magneto-transport characteristics of La1.4Ca1.6Mn2O7 thin film deposited by spray pyrolysis