Table of contents


cover image
Top

Editorial

Horizon 2020 p477

doi:10.1038/nmat3353

The next European Union funding scheme, which is pending European Council and Parliament approval by summer 2013, will be dedicated to both research and innovation.


Top

Commentaries

Two centuries of memristors pp478 - 481

Themistoklis Prodromakis, Christofer Toumazou & Leon Chua

doi:10.1038/nmat3338

Memristors are dynamic electronic devices whose nanoscale realization has led to considerable research interest. However, their experimental history goes back two centuries.


When Brownian diffusion is not Gaussian pp481 - 485

Bo Wang, James Kuo, Sung Chul Bae & Steve Granick

doi:10.1038/nmat3308

It is commonly presumed that the random displacements that particles undergo as a result of the thermal jiggling of the environment follow a normal, or Gaussian, distribution. However, non-Gaussian diffusion in soft materials is more prevalent than expected.


Top

News and Views

Colloidal self-assembly: Melting also on cooling pp487 - 488

Oleg Gang

doi:10.1038/nmat3344

Colloidal particles interacting through DNA linkers can be designed to form solids that melt when either heated or cooled. This scenario widens the temperature window in which colloidal superlattices form by reducing kinetic bottlenecks.

See also: Letter by Angioletti-Uberti et al.


Material witness: Updating the eureka p488

Philip Ball

doi:10.1038/nmat3346


X-ray scattering: In tune with organic semiconductors pp489 - 490

Stefan C. B. Mannsfeld

doi:10.1038/nmat3340

Progress in organic electronics depends on our understanding of the structure–property relationships of organic materials. Resonant scattering of polarized soft X-rays by aromatic carbon bonds has now been used to probe molecular orientation in thin organic semiconductor films down to length scales of 20 nm.

See also: Article by Collins et al.


Morphogenesis: Laying down the tracks pp490 - 492

Luke Cassereau, Christopher C. DuFort & Valerie M. Weaver

doi:10.1038/nmat3345

To drive the formation of tubular structures, cells remodel their extracellular microenvironment to induce coordinated migration. It is now found that a mechanical feedback loop, involving the interaction of cell traction forces with collagen fibres, facilitates the formation of long epithelial tubules.


Top

Letters

Possible valence-bond condensation in the frustrated cluster magnet LiZn2Mo3O8 pp493 - 496

J. P. Sheckelton, J. R. Neilson, D. G. Soltan & T. M. McQueen

doi:10.1038/nmat3329

Geometrically frustrated magnets are systems where it is impossible for all magnetic interactions to occur simultaneously. The discovery of frustrated magnetism in a system where the magnetic moments are situated across clusters of transition-metal elements instead of individual ions promises a new approach for controlling such magnetic states.

Subject term: Magnetic materials


Ultrafast transient generation of spin-density-wave order in the normal state of BaFe2As2 driven by coherent lattice vibrations pp497 - 501

K. W. Kim, A. Pashkin, H. Schäfer, M. Beyer, M. Porer, T. Wolf, C. Bernhard, J. Demsar, R. Huber & A. Leitenstorfer

doi:10.1038/nmat3294

Ultrafast and intense optical pulses have been used to study spin-density-waves in pnictide compounds, which are known to exhibit unconventional superconductivity. The results show that the magnetic order follows lattice motion, which suggests that a spin–phonon coupling may play an important role in the formation of spin-density-waves and superconductivity.

Subject terms: Magnetic materials | Superconductors


Effects of chemical bonding on heat transport across interfaces pp502 - 506

Mark D. Losego, Martha E. Grady, Nancy R. Sottos, David G. Cahill & Paul V. Braun

doi:10.1038/nmat3303

Understanding how heat is transferred across interfaces is important for the efficiency of micro- and nanoscale electronic devices. Here, it is shown that there is a direct link between the bonding character of an interface and the thermal transport across it.

Subject terms: Nanoscale materials | Surface and thin films


An oxyhydride of BaTiO3 exhibiting hydride exchange and electronic conductivity pp507 - 511

Yoji Kobayashi, Olivier J. Hernandez, Tatsunori Sakaguchi, Takeshi Yajima, Thierry Roisnel, Yoshihiro Tsujimoto, Masaki Morita, Yasuto Noda, Yuuki Mogami, Atsushi Kitada, Masatoshi Ohkura, Saburo Hosokawa, Zhaofei Li, Katsuro Hayashi, Yoshihiro Kusano, Jung eun Kim, Naruki Tsuji, Akihiko Fujiwara, Yoshitaka Matsushita, Kazuyoshi Yoshimura, Kiyonori Takegoshi, Masashi Inoue, Mikio Takano & Hiroshi Kageyama

doi:10.1038/nmat3302

The substitution of oxygen by hydride anions in oxide materials to form oxyhydrides has been difficult to achieve because it requires highly reducing conditions without transferring an electron from the hydride. An oxyhydride of BaTiO3 that is electronically conducting, stable in air and water at ambient conditions, and exchangeable with hydrogen gas at
400°C, has now been prepared.

Subject terms: Electronic materials | Materials for energy


P2-type Nax[Fe1/2Mn1/2]O2 made from earth-abundant elements for rechargeable Na batteries pp512 - 517

Naoaki Yabuuchi, Masataka Kajiyama, Junichi Iwatate, Heisuke Nishikawa, Shuji Hitomi, Ryoichi Okuyama, Ryo Usui, Yasuhiro Yamada & Shinichi Komaba

doi:10.1038/nmat3309

Although sodium is an abundant element that can be electrochemically and reversibly extracted from and inserted into layered materials, the resulting reversible capacity for storing energy remains low. A manganese–iron–sodium-based electrode is now shown to exhibit a reversible capacity of 190 mAh g−1 due to electrochemically active Fe3+/Fe4+ redox reactions.

Subject term: Materials for energy


Re-entrant melting as a design principle for DNA-coated colloids pp518 - 522

Stefano Angioletti-Uberti, Bortolo M. Mognetti & Daan Frenkel

doi:10.1038/nmat3314

The self-assembly of colloidal particles functionalized with complementary DNA strands into crystalline structures has been hampered by kinetic trapping into disordered aggregates, which effectively limits the temperature window where crystallization occurs. A strategy to design DNA-functionalized colloids with a broadened crystallization window is now proposed, and is supported by theory and simulations.

Subject terms: Colloids | Computation, modelling and theory

See also: News and Views by Gang


Top

Articles

Exchange biasing of magnetoelectric composites pp523 - 529

Enno Lage, Christine Kirchhof, Viktor Hrkac, Lorenz Kienle, Robert Jahns, Reinhard Knöchel, Eckhard Quandt & Dirk Meyners

doi:10.1038/nmat3306

Magnetoelectric composite materials are of interest for sensitive magnetic-field sensors. The realization of a magnetoelectric composite that does not require an applied external magnetic field, but instead relies on internal bias via exchange coupling, promises sensitive sensors even for small magnetic fields.

Subject terms: Electronic materials | Magnetic materials


Atomically controlled electrochemical nucleation at superionic solid electrolyte surfaces pp530 - 535

Ilia Valov, Ina Sapezanskaia, Alpana Nayak, Tohru Tsuruoka, Thomas Bredow, Tsuyoshi Hasegawa, Georgi Staikov, Masakazu Aono & Rainer Waser

doi:10.1038/nmat3307

Studying electrochemical equilibria at interfaces on the atomic scale is crucial for understanding physicochemical processes, but such investigations are currently limited by phase instabilities and instrumentation. A small amount of electron donors in a solid electrolyte is now shown to enable scanning tunnelling microscope measurements and atomically resolved imaging.

Subject terms: Materials for energy | Surface and thin films | Characterisation and analytical techniques


Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films pp536 - 543

B. A. Collins, J. E. Cochran, H. Yan, E. Gann, C. Hub, R. Fink, C. Wang, T. Schuettfort, C. R. McNeill, M. L. Chabinyc & H. Ade

doi:10.1038/nmat3310

Molecular orientation, which critically influences the properties of organic materials, could until now only be characterized if the sample exhibited sufficient crystallinity. Resonant scattering of polarized soft X-rays by aromatic carbon bonds has now been used to probe non-crystalline ordering and molecular orientation in thin films with a resolution down to 20 nm.

Subject terms: Polymers | Surface and thin films | Characterisation and analytical techniques

See also: News and Views by Mannsfeld


Room-temperature metastability of multilayer graphene oxide films pp544 - 549

Suenne Kim, Si Zhou, Yike Hu, Muge Acik, Yves J. Chabal, Claire Berger, Walt de Heer, Angelo Bongiorno & Elisa Riedo

doi:10.1038/nmat3316

Graphene oxide could potentially be used for numerous applications, particularly in electronics. Understanding its structural stability in an ambient atmosphere is essential for the realization of devices. A new study shows that multilayer graphene oxide is in fact metastable at room temperature.

Subject terms: Nanoscale materials | Electronic materials


Trends in activity for the water electrolyser reactions on 3d M(Ni,Co,Fe,Mn) hydr(oxy)oxide catalysts pp550 - 557

Ram Subbaraman, Dusan Tripkovic, Kee-Chul Chang, Dusan Strmcnik, Arvydas P. Paulikas, Pussana Hirunsit, Maria Chan, Jeff Greeley, Vojislav Stamenkovic & Nenad M. Markovic

doi:10.1038/nmat3313

Efficient electrochemical transformation of water to molecular hydrogen and of hydroxyl ions to oxygen in alkaline environments is important for reducing energy losses in water–alkali electrolysers. Insight into the activities of hydr(oxy)oxides on platinum catalyst surfaces for hydrogen and oxygen evolution reactions should prove significant for designing practical alkaline electrocatalysts.

Subject terms: Catalytic materials | Semiconductors


Top