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Oscillations in the exchange coupling between ferromagnetic La 2/3 Ba 1/3 M nO3 layers with paramagnetic LaN iO3 spacer layer thickness has been observed in epitaxial heterostructures of the two oxides. This behavior is explained within the RKKY model employing an ab initio calculated band structure of LaN iO3, taking into account strong electron scattering in the spacer. Antiferromagnetically coupled superlattices exhibit a positive current-in-plane magnetoresistance. 75.70.Cn, 75.30.Vn, 71.18.+y, 75.70.Pa Since the discovery of giant magnetoresistance [1] and oscillatory interlayer coupling [2], metallic magnetic multilayers have been the subject of intensive research [3]. A physical picture of the coupling is provided in terms of quantum interference due to confinement of electrons in the nonmagnetic spacers [4,5]. Ruderman-KittelKasuya-Yosida (RKKY) theory [6], successfully used to describe the effect, appears to be a limiting case of a more general approach [5]. The prediction that oscillations periods are determined by the extremal spanning vectors of the Fermi surface of the nonmagnetic spacer is now supported by a wealth of experimental data [7]. The phase and magnitude of the coupling oscillations apparently are sensitive to the interface matching of the electron bands for a particular magnetic configuration of the layers [3][4][5].While these effects have been studied in many simple metal and alloy systems, little progress has been achieved in investigating them in multilayers consisting entirely of compounds [8]. In this Letter we report the first observation of oscillatory coupling in heterostructures fabricated entirely of oxides, thus extending the field to a novel class of materials. The ferromagnetic layer material, barium-doped lanthanum manganese oxide La 2/3 Ba 1/3 M nO 3 belongs to the family of metallic manganese oxides that exhibit very large (colossal) magnetoresistance [9]. Double exchange ferromagnetism [10] predicts half-metallicity in these compounds, which has been justified by ab initio band structure calculations [11] as well as confirmed (to a certain degree) experimentally [12]. As a spacer layer material, we have employed LaN iO 3 , which is lattice-matched to La 2/3 Ba 1/3 M nO 3 , and is the only rare earth nickelate that is a paramagnetic metal [13]. Its susceptibility is strongly enhanced by electron-electron exchange interactions [14]. In thin film form, it is a better conductor (resistivity of 50 − 100 µΩ · cm) than the manganites (resistivity of 300 − 500 µΩ · cm). Although advances in oxide film growth permit the fabrication of atomically defined layered structures with nanometer scale periodicity [15], the very strict control over stoichiometry and deposition conditions required to produce multilayers remains a significant experimental challenge.In our previous paper [16] we presented the evidence for antiferromagnetic (AFM) interlayer coupling in this system. Here we demonstrate that the initially AFM coupling becomes ferromagnetic (FM) at larger spacer thicknesses a...

Magnetic memory based on La 0.7 Ca 0.3 MnO 3 / YBa 2 Cu 3 O 7 / La 0.7 Ca 0.3 MnO 3 ferromagnet/superconductor hybrid structures Appl. Phys. Lett. 97, 032501 (2010); 10.1063/1.3464960 Spin wave scattering and interface magnetism in superconducting-ferromagnet-superconducting hybrid structures

A materials system of ternary full Heusler alloys exhibiting substantial current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) has been theoretically proposed and experimentally realized. Observed trends in magnetoresistance are broadly consistent with the modeling results. A CPP-GMR of 6.7% and ΔRA of 4 mΩ μm2 have been demonstrated in the bottom spin-valve configuration. The spin-stand testing of narrow-track recording heads confirmed compatibility of these materials with hard disk drive reader technology.

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