Journal ArticleDOI
Engineered interface of magnetic oxides.
Hiroyuki Yamada,Yoshihiro Ogawa,Yuji Ishii,Hiroshi Sato,Masashi Kawasaki,Masashi Kawasaki,Hiroshi Akoh,Yoshinori Tokura,Yoshinori Tokura +8 more
TLDR
By grading the doping profile on an atomic scale at the interface, robust ferromagnetism can be realized around room temperature and should lead to improvements in the performance of spin-tunnel junctions.Abstract:
Interface-selective probing of magnetism is a key issue for the design and realization of spin-electronic junction devices. Here, magnetization-induced second-harmonic generation was used to probe the local magnetic properties at the interface of the perovskite ferromagnet La0.6Sr0.4MnO3 with nonmagnetic insulating layers, as used in spin-tunnel junctions. We show that by grading the doping profile on an atomic scale at the interface, robust ferromagnetism can be realized around room temperature. The results should lead to improvements in the performance of spin-tunnel junctions.read more
Citations
More filters
Journal ArticleDOI
Revival of the Magnetoelectric Effect
Abstract: Recent research activities on the linear magnetoelectric (ME) effect?induction of magnetization by an electric field or of polarization by a magnetic field?are reviewed. Beginning with a brief summary of the history of the ME effect since its prediction in 1894, the paper focuses on the present revival of the effect. Two major sources for 'large' ME effects are identified. (i) In composite materials the ME effect is generated as a product property of a magnetostrictive and a piezoelectric compound. A linear ME polarization is induced by a weak ac magnetic field oscillating in the presence of a strong dc bias field. The ME effect is large if the ME coefficient coupling the magnetic and electric fields is large. Experiments on sintered granular composites and on laminated layers of the constituents as well as theories on the interaction between the constituents are described. In the vicinity of electromechanical resonances a ME voltage coefficient of up to 90?V?cm?1?Oe?1 is achieved, which exceeds the ME response of single-phase compounds by 3?5 orders of magnitude. Microwave devices, sensors, transducers and heterogeneous read/write devices are among the suggested technical implementations of the composite ME effect. (ii) In multiferroics the internal magnetic and/or electric fields are enhanced by the presence of multiple long-range ordering. The ME effect is strong enough to trigger magnetic or electrical phase transitions. ME effects in multiferroics are thus 'large' if the corresponding contribution to the free energy is large. Clamped ME switching of electrical and magnetic domains, ferroelectric reorientation induced by applied magnetic fields and induction of ferromagnetic ordering in applied electric fields were observed. Mechanisms favouring multiferroicity are summarized, and multiferroics in reduced dimensions are discussed. In addition to composites and multiferroics, novel and exotic manifestations of ME behaviour are investigated. This includes (i) optical second harmonic generation as a tool to study magnetic, electrical and ME properties in one setup and with access to domain structures; (ii) ME effects in colossal magnetoresistive manganites, superconductors and phosphates of the LiMPO4 type; (iii) the concept of the toroidal moment as manifestation of a ME dipole moment; (iv) pronounced ME effects in photonic crystals with a possibility of electromagnetic unidirectionality. The review concludes with a summary and an outlook to the future development of magnetoelectrics research.
Journal ArticleDOI
Emergent phenomena at oxide interfaces
TL;DR: Recent technical advances in the atomic-scale synthesis of oxide heterostructures have provided a fertile new ground for creating novel states at their interfaces, with characteristic feature is the reconstruction of the charge, spin and orbital states at interfaces on the nanometre scale.
Journal ArticleDOI
Complexity in Strongly Correlated Electronic Systems
TL;DR: The spontaneous emergence of electronic nanometer-scale structures in transition metal oxides, and the existence of many competing states, are properties often associated with complex matter where nonlinearities dominate, such as soft materials and biological systems.
Journal ArticleDOI
Bio-Inspired, Smart, Multiscale Interfacial Materials
TL;DR: In this article, a strategy for the design of bioinspired, smart, multiscale interfacial (BSMI) materials is presented and put into context with recent progress in the field of BSMI materials spanning natural to artificial to reversibly stimuli-sensitive interfaces.
Journal ArticleDOI
Strong polarization enhancement in asymmetric three-component ferroelectric superlattices
TL;DR: The data reveal that the specific interface structure and local asymmetries play an unexpected role in the polarization enhancement, and it is shown that even superlattices containing only single-unit-cell layers of BaTiO3 in a paraelectric matrix remain ferroelectric.
References
More filters
Journal ArticleDOI
Insulator-metal transition and giant magnetoresistance in La 1-x Sr x MnO 3
TL;DR: Insulator-metal phenomena depending on band filling, temperature, and external magnetic field have been investigated for prototypical double-exchange ferromagnets, namely, crystals of crystals of La 1-x, showing large negative magnetoresistance around the ferromagnetic transition temperature.
Journal ArticleDOI
Artificial charge-modulationin atomic-scale perovskite titanate superlattices
TL;DR: It is found that a minimum thickness of five LaTiO3 layers is required for the centre titanium site to recover bulk-like electronic properties, and this represents a framework within which the short-length-scale electronic response can be probed and incorporated in thin-film oxide heterostructures.
Journal ArticleDOI
Nearly total spin polarization in La2/3Sr1/3MnO3 from tunneling experiments
Martin Bowen,Manuel Bibes,Alain Barthélémy,J.-P. Contour,Abdelmadjid Anane,Y. Lemaitre,Albert Fert +6 more
TL;DR: In this paper, a magnetoresistance ratio of more than 1800% is obtained at 4 K, from which they infer an electrode spin polarization of at least 95% and demonstrate the half-metallic nature of mixed-valence manganites and demonstrates their capability as a spin analyzer.
Journal ArticleDOI
Observation of large low‐field magnetoresistance in trilayer perpendicular transport devices made using doped manganate perovskites
Jonathan Z. Sun,William J. Gallagher,P. R. Duncombe,L. Krusin-Elbaum,R. A. Altman,Ayush Gupta,Yu Lu,G. Q. Gong,Gang Xiao +8 more
TL;DR: In this paper, a trilayer epitaxial thin film device based on the doped perovskite manganates La-Ca-Mn-O and La-Sr-mn−O was constructed and large resistance changes, up to a factor of 2, can be induced by a moderate applied magnetic field below 200 Oe in these trilayers supporting current-perpendicular-to-plane transport.
Journal ArticleDOI
Ferromagnetism in LaFeO3-LaCrO3 Superlattices
TL;DR: Ferromagnetic spin order has been realized in the LaCrO3-LaFeO3 superlattices and ferromagnetic ordering has been achieved in Fe3+ and Cr3+ layer along the [111] direction.