Magnetic materials for spintronic devices

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  Gate-tunable quantum oscillations in ambipolar Cd₃As₂ thin films

  Cd₃As₂, which is known as a topological Dirac semimetal, has been grown on mica substrates by molecular beam epitaxy with high mobility. The temperature-dependent resistance of as-grown Cd₃As₂ thin films showed semiconducting behavior, indicating the band gap opening as opposed to the bulk counterpart. By solid electrolyte gating, the ambipolar effect and gate-tunable quantum oscillations were clearly demonstrated. These features make the Cd₃As₂ thin film system a promising platform to observe various exotic phenomena and realize new electronic applications.

  • Yanwen Liu
  • Cheng Zhang
  • Faxian Xiu

  Original ArticleOpen Access30 Oct 2015 NPG Asia Materials
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  Electric-field switching of perpendicularly magnetized multilayers

  Reversible electric-field-driven magnetization switching between perpendicular-to-plane and in-plane orientations in Cu/Ni multilayers on ferroelectric BaTiO₃ is demonstrated at room temperature. Fully deterministic magnetic switching is based on efficient strain transfer from ferroelastic domains in BaTiO₃ and the high sensitivity of perpendicular magnetic anisotropy in Cu/Ni to electric-field-induced strain modulations. The magnetoelectric coupling effect can also be used to realize 180° magnetization reversal if the out-of-plane symmetry of magnetic anisotropy is temporarily broken by a small magnetic field.

  • Yasuhiro Shirahata
  • Ryota Shiina
  • Tomoyasu Taniyama

  Original ArticleOpen Access10 Jul 2015 NPG Asia Materials
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  Unraveling how electronic and spin structures control macroscopic properties of manganite ultra-thin films

  The interplay between hybridization, orbital occupancy and spin that governs the macroscopic transport and magnetic properties of ultra-thin manganites is revealed using a combination of spectroscopic ellipsometry, X-ray absorption, X-ray magnetic circular dichroism and transport measurements.

  • Xinmao Yin
  • Muhammad Aziz Majidi
  • Andrivo Rusydi

  Original ArticleOpen Access3 Jul 2015 NPG Asia Materials
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  Functional helical silica nanofibers with coaxial mixed mesostructures for the fabrication of PtCo nanowires that display unique geometry-dependent magnetism

  A novel confinement-free synthesis of CP-HMNSFs possessing straight channels at fiber center surrounded by concentric short-pitch helical channels is discovered. The chloropropyl groups are found mainly located at central cylindrical part of the nanofibers. Helical PtCo nanowires with small and narrowly distributed radii of gyration are also fabricated, showing distinct ferromagnetic properties as compared with the straight counterparts.

  • Nien-Chu Lai
  • Sz-Chian Liou
  • Chia-Min Yang

  Original ArticleOpen Access22 May 2015 NPG Asia Materials
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  Beating the Stoner criterion using molecular interfaces

  By harnessing the charge transfer that takes place at the interface between a metal and a layer of molecules, the usually non-magnetic materials copper and manganese are made magnetic at room temperature.

  • Fatma Al Ma’Mari
  • Timothy Moorsom
  • Oscar Cespedes

  Letter5 Aug 2015 Nature
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  Optically reconfigurable magnetic materials

  The periodic modulation of the magnetic properties of magnonic crystals controls the flow of spin waves. An optical method is now shown that can produce such modulations by heating, which can be reprogrammed during operation.

  • Marc Vogel
  • Andrii V. Chumak
  • Georg von Freymann

  Letter18 May 2015 Nature Physics
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  Design of compensated ferrimagnetic Heusler alloys for giant tunable exchange bias

  An approach to design compensated ferrimagnetic Heusler alloys is established. A small lack of compensation produces giant exchange bias and large coercivity. This effect is observed for alloys that have the magnetic transition above room temperature.

  • Ajaya K. Nayak
  • Michael Nicklas
  • Claudia Felser

  Letter16 Mar 2015 Nature Materials
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  Efficient thermal spin injection using CoFeAl nanowire

  Efficient thermal spin injection can be achieved by using CoFeAl alloy in which the sign of the Seebeck coefficients for up and down spins are opposite each other.

  • Shaojie Hu
  • Hiroyoshi Itoh
  • Takashi Kimura

  Original ArticleOpen Access19 Sep 2014 NPG Asia Materials
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  Quantum spin Hall insulators and quantum valley Hall insulators of BiX/SbX (X=H, F, Cl and Br) monolayers with a record bulk band gap

  A group of 2D topological insulators BiX/SbX (X=H, F, Cl and Br) monolayers with extraordinarily large bulk gaps from 0.32 to a record value of 1.08 eV were predicated. These giant-gaps result from the strong spin-orbit interaction related to p_x and p_y orbitals of Bi/Sb atoms around the two valleys K and K′. The honeycomb structures of BiX monolayers remain stable even at a temperature of 600 K. The electric field-biased BiX/SbX monolayers become quantum valley Hall insulators, showing valley-selective circular dichroism. These features make the BiX/SbX monolayers an ideal platform to realize many exotic phenomena and fabricate new quantum devices.

  • Zhigang Song
  • Cheng-Cheng Liu
  • Yugui Yao

  Original ArticleOpen Access12 Dec 2014 NPG Asia Materials