U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Craig Brown (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 76 - 100 of 158

Selective Hydride Occupation in BaVO 3-x H x (0.3 less than or equal to}xless than or equal to}0.8) with Face- and Corner-Shared Octahedra

March 13, 2018
Author(s)
Takafumi Yamamoto, Kazuki Shitara, Shunsaku Kitagawa, Akihide Kuwabara, Masahiro Kuroe, Kenji Ishida, Masayuki Ochi, Kazuhiko Kuroki, Kotaro Fujii, Masatomo Yashima, Craig Brown, Hiroshi Takatsu, Tassel Cedric, Hiroshi Kageyama
A growing number of transition metal oxyhydrides have recently been reported, but they are all confined to perovskite-based structures with corner-shared octahedra. Using high pressure synthesis, we have obtained vanadium oxhydrides BaVO 3-xH x(0.3less

Unravelling Solid-State Redox Chemistry in Li 1.3 Nb 0.3 Mn 0.4 O 2 Single-Crystal Cathode Material

March 13, 2018
Author(s)
Wang Hay Kan, Dongchang Chen, Joseph K. Papp, Alpesh Khushalchand Shukla, Ashfia Huq, Craig Brown, Bryan D. McCloskey, Guoying Chen
Recent reports on high capacities delivered by Li-excess transition-metal oxide cathodes have triggered intense interest in utilizing reversible oxygen redox for high-energy battery applications. In order to control oxygen electrochemical activities

Rapid Microwave Preparation and Composition Tuning of the High-Performance Magnetocalorics (Mn,Fe) 2 (P,Si)

February 28, 2018
Author(s)
Jason H. Grebenkemper, Joshua D. Bocarsly, Emily E. Levin, Gareth Seward, Colin A. Heikes, Craig Brown, Sumohan Misra, Fabian Seeler, Kerstin Schierle-Arndt, Stephen D. Wilson, Ram Seshadri
A rapid preparation utilizing assisted microwave heating has been developed for (Mn,Fe) 2(P,Si) and used to prepare samples of (Mn,Fe) 2-δPd0.5^Si 0.5 with δ=0, 0.06, and 0.12. To fully understand the effects of processing and composition changes on

H 2 Adsorption on Cu(I)-SSZ-13

January 11, 2018
Author(s)
Bahar Ipek, Rachel A. Pollock, Craig Brown, Deniz Uner, Raul F. Lobo
We report H 2 adsorption capacities reaching 0.05 mass% (wt. %) at 303 K and 1 atm H 2 pressure on solid-state CuCl-exchanged [Al]-SSZ-13 and [B]-SSZ zeolites. Differential heat of H 2 adsorption is found in the range between 16 KJ mol H 2 -1 and 48 KJ mol

Pressure Tuning of Collapse of Helimagnetic Structure in Au 2 Mn

November 27, 2017
Author(s)
I Lin NMN Liu, Maria J. Pascale, Juscelino Leao, Craig Brown, William D. Ratcliff, Qingzhen Huang, Nicholas Butch
We identify the phase boundary between spiral spin and ferromagnetic phases in Au 2Mn at a critical pressure of 16.4 kbar, as determined by neutron diffraction, magnetization and magnetoresistance measurements. The temperature-dependent critical field at a

Electronic Conductivity in a Porous Vanadyl Prussian Blue Analogue upon Air Exposure

November 6, 2017
Author(s)
Mary Anne Manumpil, Carmen Leal-Cervantes, Matthew R. Hudson, Craig Brown, Hemamala I. Karunadasa
Exposure to humid oxygen or ambient air affords a 5-or-der-of-magnitude increase in the electronic conductivity of a new Prussian blue analog incorporation Co(II) and V(IV)-oxo units. Oxidation produces a mixed-valence framework, where the oxygen exposure

Selective Gas Adsorption in Highly Porous Chromium(II)-Based Metal-Organic Polyhedra

September 27, 2017
Author(s)
Gregory R. Lorzing, Benjamin Trump, Craig Brown, Eric D. Bloch
The synthesis and characterization of two novel chromium(II)-based cuboctahedral metal-organic polyhedra is reported. The alkane functionalized analog, Cr_ tBu-bdc ( tBu-bdc = 5-tertbutylbenzene-1,3-dicarboxylate) exhibits excellent thermal stability

Origin of Long Lifetime of Band-Edge Charge Carriers in organic-Inorganic Lead Iodide Perovskites

July 17, 2017
Author(s)
Tianran Chen, Wei-Liang Chen, Benjamin J. Foley, Jooseop Lee, Jacob P. C. Ruff, J. Y. Peter Ko, Craig Brown, Leland Harriger, Depei Zhang, Changwon Park, Mina Yoon, Yu-Ming Chang, Joshua J. Choi, Seung-Hun Lee
Long carrier lifetime is what makes hybrid organic-inorganic perovskites (HOIPs) high performance photovoltaic materials. The microscopic mechanism behind the unusually long carrier lifetime of greater than equal to} 1 υs is not well understood. Here we

Formation of [Cu 2 O 2 ] 2+ and [Cu 2 O] 2+ Toward C-H Bond Activation in Cu-SSZ-13 and Cu-SSZ-39

July 7, 2017
Author(s)
Bahar Ipek, Matthew J. Wulfers, Hacksung Kim, Florian Goeltl, Ive Hermans, Joseph P. Smith, Karl S. Booksh, Craig Brown, Raul F. Lobo
Cu- exchanged small-pore zeolites (CHA and AEI) form methanol from methane (>95% selectivity) using a 3-step cyclic procedure (Wulfers, M. J.; Teketel, S.; Ipek, B.; Lobo, R. F. Chem. Commun. 2015, 51, 4447–4450) with methanol amounts higher than Cu- ZSM-5

Metal-Insulator Transition Tuned by Magnetic Field in Bi 1.7 V 8 O 16 Hollandite

May 1, 2017
Author(s)
Amber M. Larson, Brandon Wilfong, Pouya Moetakef, Craig Brown, Peter Zavalij, Efrain E. Rodriguez
We describe a metal-insulator transition for a quasi-one dimensional system containing a mix of S = 1 and S=1/2 vanadium cations. Unlike all other known vanadates, Bi 1.7V 8O 16 displays non-spin-singlet formation upon entering the insulating state

Performance of van der Waals Corrected Functionals for Guest Adsorption in the M 2 (dobdc) Metal-Organic Frameworks

April 24, 2017
Author(s)
Bess Vlaisavljevich, Johanna Huck, Zeric Hulvey, Kyuho Lee, Jarad A. Mason, Jeffrey B. Neaton, Jeffrey R. Long, Craig Brown, Dario Alfe, Angelos Michaelides, Berend Smit
Small molecule binding in metal-organic frameworks (MOFs) can be accurately studied both experimentally and computationally, provided the proper tools are employed. Herein, we compare and contrast properties associated with guest binding with density

Combining Microscopic and Macroscopic Probes to Untangle the Single-Ion Anisotropy and Exchange Energies in an S = 1 Quantum Antiferromagnet

April 20, 2017
Author(s)
Jamie Brambleby, Jamie Lee Manson, Paul A. Goddard, Matthew B. Stone, Roger D. Johnson, Pascal Manuel, Jacquelina A. Villa, Craig Brown, Helen Lu, Shalinee Chikara, Vivien Zapf, Saul H. Lapidus, Rebecca Scatena, Piero Macchi, Yu-Sheng Chen, Lai-Chin Wu, John Singleton
We derive a synergistic approach to determine the spin Hamiltonian and field-temperature phase diagram for polycrystalline samples of S = 1 [Ni(HF 2)(pyz) 2]SbF 6 by exploiting a selected range of experimental techniques. Spatial exchange anisotropy was

Ising-Like Antiferromagnetism on the Octahedral Sublattice of a Cobalt-Containing Garnet and the Potential for Quantum Critically

April 14, 2017
Author(s)
Abbey J. Neer, Joanna Milam-Guerrero, Justin E. So, Brent C. Melot, Kate Ross, Zeric Hulvey, Craig Brown, Alexey A. Sokol, David O. Scanlon
In this letter, we report the observation of quasi-one-dimensional magnetism in the garnet CaY 2Co 2Ge 3O 12. Using low-temperature powder neutron diffraction and symmetry analysis, we identify a magnetic structure consisting of chain-like motifs oriented

Cubic Lead Perovskite PbMoO 3 with Anomalous Metallic Behavior

April 1, 2017
Author(s)
Hiroshi Takatsu, Olivier Hernandez, Wataru Yoshimune, Carmelo Prestipino, Takafumi Yamamoto, Cedric Tassel, Yoji Kobayashi, Dmitry Batuk, Yuki Shibata, Artem M. Abakumov, Craig Brown, Hiroshi Kageyama
A novel Pb-based perovskite PbMoO 3 is obtained by high-pressure and high-temperature synthesis. This material crystallizes in the Pm3m cubic structure at room temperature, making it distinct from typical Pb-based perovskite oxides with a structural

Metastable Layered Cobalt Chalcogenides from Topochemical Deintercalation

November 29, 2016
Author(s)
Xiuquan Zhou, Brandon Wilfong, Hector Vivanco, Johnpierre Paglione, Craig Brown, Efrain E. Rodriguez
We present a general strategy to synthesize metastable layered materials via topochemical de-intercalation of thermodynamically stable to phases.Through kinetic control of the de-intercalation reaction, we have prepared two hypothesized metastable

ZnTaO 2 N: Stabilized High-Temperature LiNbO 3 -Type Structure

November 18, 2016
Author(s)
Yoshinori Kuno, Cedric Tassel, Koji Fujita, Dmitry Batuk, Artem M. Abakumov, Kazuki Shitara, Akihide Kuwabara, Hiroki Moriwake, Daichi Watabe, Clemens Ritter, Craig Brown, Takafumi Yamamoto, Fumitaka Takeiri, Ryu Abe, Yoji Kobayashi, Katsuhisa Tanaka, Hiroshi Kageyama
By using a high pressure reaction, we prepared a new oxynitride ZnToO 2N that crystallizes in a centrosymmetric (R-3 c)high-temperature LiNbO 3-type structure (HTLN-type). The stabilization of the HTLN-type structure down to low temperatures (at least 20 K

Entropy-Driven Structural Transition and Kinetic Trapping in Formamidinium Lead Iodide Perovskite

October 21, 2016
Author(s)
Tianran Chen, Benjamin J. Foley, Changwon Park, Craig Brown, Leland Harriger, Jooseop Lee, Jacob Ruff, Mina Yoon, Joshua J. Choi, Seugn-Hun Lee
A challenge for hybrid perovskite solar cells is device instability, which calls for understanding of the perovskite structural stability and phase transitions. Here, using neutron diffraction and ab-initio calculations on HC(NH 2) 2PbI 3, we show that the

Three-Dimensional Protonic Conductivity in Porous Organic Cage Solids

September 13, 2016
Author(s)
Ming Liu, Linjiang Chen, Scott Lewis, Samantha Y. Chong, Marc A. Little, Tom Hasell, Iain M. Aldous, Craig Brown, Martin W. Smith, Carole A. Morrison, Laurence J. Hardwick, Andrew I. Cooper
Proton conduction is a fundamental process in biology and in devices such as proton exchange membrane fuel cells. To maximize proton conduction, 3-D conduction pathways are preferred over 1-D pathways, which prevent proton conduction in two-dimensions

The Low-Temperature Structural Behavior of Sodium 1-Carba-closo-decaborate: NaCB 9 H 10

August 21, 2016
Author(s)
Hui Wu, Wan Si NMN Tang, Wei Zhou, Jacob Daniel Tarver, Vitalie Stavila, Craig Brown, Terrence J. Udovic
Two ordered phases of the novel solid superionic conductor sodium 1-carba-closo-decaborate (NaCB 9H 10) were identified via synchrotron x-ray powder diffraction in combination with first-principles calculations and neutron vibrational spectroscopy. A

Hydrogen Storage and Selective, Reversible O 2 Adsorption in a Metal-Organic Framework with Open Chromium(II) Sites

July 18, 2016
Author(s)
Eric D. Bloch, Wendy L. Queen, Matthew Ross Hudson, Jarad A. Mason, Dianne J. Xiao, Leslie J. Murray, Roxana Flacau, Craig Brown, Jeffrey R. Long
A chromium(II)-based metal-organic framework, Cr 3[Cr 4Cl) 3(BTT) 8] 2 (Cr-BTT;BTT 3- = 1,3,5-benzenetrisetrazolate), featuring coordinatively-unsaturated, redox-active Cr 2+ cation sites was synthesized and investigated for potential applications in H 2

Quasi-Elastic Neutron Scattering Studies of Hydrogen Dynamics for Nanoconfined NaAlH 4

July 14, 2016
Author(s)
Shathabish NaraseGowda, Craig Brown, Madhu Sudan Tyagi, Tabbetha A. Dobbins
The hydrogen dynamics of nano-confined sodium alanate (NaAlH 4) has been studied using quasi-elastic neutron scattering (QENS). Results indicate thermodynamic destabilization is responsible for reduced desorption temperatures of NaAlH 4 upon confinement

Adsorption of Two Gas Molecules at a Single Metal Site in a Metal-Organic Framework

July 7, 2016
Author(s)
Tomce Runcevski, Matthew T. Kapelewski, Rodolfo M. Torres-Gavosto, Jacob Daniel Tarver, Craig Brown, Jeffrey R. Long
One strategy to markedly increase the gas storage capacity of metal-organic frameworks, is to introduce coordinatively-unsaturated metal centers capable of binding multiple gas molecules. Herein, we provide an initial demonstration that a single mental