Functional Inorganic Materials at UMD

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News

August 2019 Congratulations to the two newest doctors from the Rodriguez Group. Dr. Austin Virtue and Dr. Rishvi Jayathilake. Dr. Virtue's Ph.D. thesis titled "Structure and Properties of Alloyed Chalcogenides with the ThCr2Si2 type structure and Dr. Jayathilake's Ph.D. thesis was titled "Oxygen Storage Properties of Ternary Metal Oxide Systems for Chemical Looping Reactions" .

June 2019 Our work on spherical neutron polarimetry in conjunction with the NIST Center for Neutron Research was published in Review of Scientific Instruments titled "Small-angle neutron polarimetry apparatus (SANPA): Development at the NIST Center for Neutron Research" .

April 2019 Our work on tetrahedral transition metal chalcogenide materials was published in Physical Review Materials titled "Magnetic order effects on the electronic structure of KMMnS2(M=Cu,Li) with the ThCr2Si2-type structure" .

April 2019 Our latest work on chemical looping reactions was published in Chemical Communications titled "Structural studies of the perovskite series La1-xSrxCoO3-d during chemical looping with methane".

January 2019 Our review work on ferrotorodicity was published in Journal of Solid State Chemistry titled "The fourth ferroic order: Current status on ferrotoroidic materials".

August 2018 Congratulations to senior graduate student Stephanie Gnewuch for winning the Margaret C. Etter Student Lecture Award in Neutron Scattering at the American Crystallographic Association National meeting for her talk on synthesis and characterization of transition metal phosphates.

May 2018 Congratulations to the newest doctor from the Rodriguez Group, Dr. Xiuquan Zhou on the successful defense of his thesis on Intecalation Chemistry of Transition Metal Chalcogenides and winning the 'Research Excellence Award' from the University of Maryland Department of Chemistry and Biochemistry.

April 2018 Our latest work on intercalation in Fe-based superconductors was published in Chemical Communications titled "Proton and ammonia intercalation into layered iron chalcogenides".

March 2018 Our work on new layered transition metal chalcogenides was published in Physical Review B titled "Frustrated magnetism in the tetragonal CoSe analog of superconducting FeSe".

February 2018 Our work on solid-state oxygen storage materials was published in Journal of Materials Chemistry A titled "In situ diffraction studies on reversible oxygen uptake and release in AFe2O4+δ ( A = Lu, Yb, Y, In)".

October 2017 Congratulations to Rishvi Jayathilake for winning the student poster prize at the 75th Annual Pittsburgh Diffraction Conference! Her poster was titled "Oxygen Storage Properties of RFe2O4 (R = Lu, Yb, Y, and In)".

June 2017 Our perspective article on layered metal chalcogenides was published in Chemistry of Materials as part of their Up-and-Coming series. "Tetrahedral Transition Metal Chalcogenides as Functional Inorganic Materials".

June 2017 Congratulations to Dan for successfully defending his Ph.D. thesis "Structural and Chemical Factors Governing Anion Reactivity in Perovskite Oxides".

May 2017 Congratulations to Amber for successfully defending her Ph.D. thesis "Frustrated Magnetism and Electronic Properties of Hollandite Oxide Materials".

May 2017 Our work on an interesting metal-to-insulator transition in a metal oxide was published in Journal of Materials Chemistry C titled "Metal-insulator transition tuned by magnetic field in Bi1.7V8O16 hollandite".

March 2017 Our work on superconducting and new layered iron suflides was published as an Edge Article in Chemical Science titled "Superconductivity and magnetism in iron sulfides intercalated by metal hydroxides".

Research projects:

Solid-state materials can transform how we communicate, utilize energy, and store information. Before being integrated into exciting applications, every advanced material must first be developed by fundamental science and engineering. At the University of Maryland, our group uses a multidisciplinary approach for the preparation and study of functional inorganic materials. We design and synthesize energy-related materials and novel quantum materials, where interactions at the atomic scale have profound consequences for their macroscopic properties. With advanced neutron measurements of our materials, we investigate what is so unique about their crystal structures that give rise to their advanced physical properties. Finally, we have strong collaborations with UMD Physics and the nearby National Institute of Standards and Technology (NIST) to deepen the impact of our science. Below are specific directions our group currently pursues.

Research area 1: Tetrahedral transition metal chalcogenides for superconductivity and magnetism

Team members: Brandon Wilfong, Huafei Zheng, Lahari Balisetty, and Justin Yu

The development of superconductivity at a high enough temperature would revolutionize the electrical grid by creating highly efficient power lines. In addition to this extraordinary property, superconductors can create large, stable magnetic fields, which already have utility in medical technologies such as magnetic resonance imaging (MRI). To fulfill potential future applications, we must find compounds with optimal properties such as a high enough Tc to make practical devices. Our group synthesizes transition metal chalcogenides with layered-type structures in order to prepare new superconductors or related physical properties. With advanced measurements that include synchrotron X-rays and neutrons, we study the key structure-property relationships of our superconducting materials. In addition, we find novel chemical route towards the preparation of single crystals of our materials. Common to all of our superconductors is the similarity in their crystal structures. In these chalcogenides, the M2+ ions are in tetrahedral coordination, and those MCh4 tetrahedra are edge-sharing. For the 2D materials, we are primarily interested in how to build new heterestructures to manipualte the magnetism and superconductivity. For the 3D materials, we are interested in the fundamental interactions between the magnetism and itinerant electrons. In all cases, we are looking to find new synthetic routes towards new materials and single crystal growth. (Click here) to see our our latest papers on these materials. Below, a schematic of the topochemical reactions to achieve different phases of layered iron chalcogenides.

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Research area 2: Uncovering Ferrotoroidic Ordering through Targeted Materials Synthesis and Polarized Neutron Diffraction

Team members: Stephanie Gnewuch, Timothy Diethrich, and Jacob Tosado

Ferroics such as ferromagnets, ferroelectrics, and ferroelastics are crystalline materials whose characteristic properties are dictated by and understood through their symmetry. A defining characteristic of these materials are that the magnetic moments, electric dipoles, etc. will spontaneously align at a specific transition temperature. This ordering is used to both understand the orientation of their spontaneous physical properties, and properties under applied fields. Through the lens of solid-state chemistry, we are searching for a new class of ferroic materials called ferrotoroidics. We define a toroidal moment as the local moment that arises from a local vortex of magnetic moments. When considering materials to target for synthesis, we consider both the point group symmetry which would permit novel ordering, and structural components which enable this ordering. We began by studying the series of lithium transition metal orthophosphates LiMPO4 (M = Mn, Fe, Co, Ni), whose magnetic point group symmetry is known to permit ferrotoroidic order in the iron, cobalt, and nickel analogs. We have begun also investigating other systems also containing magnetic transition metal cations and tetrahedral anions, such as thiophosphates, silicates, and pyroxenes. The figure below depicts two candidate structures for ferrotoroidics. To study the subtle features of the magnetic ordering in our materials, we are currently building the polarized neutron apparatus and infrastructure to perform spherical neutron polarimetry on these and other materials.

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Research area 3: in-situ x-ray and Neutron Diffraction

Team members: Tianyu Li, Lahari Balisetty and Brandon Wilfong

In addition to synthesizing new materials, we also develop new techinques for studying the formation of these materials using high resolution x-ray and neutron diffraction. To do this, our group performs extensive in-situ reactions with both neutrons and synchrotron X-rays to study the kinetics and thermodynamic properties of the formation of these materials at high temperatures, pressures and solvent environments. From these in situ and fast diffraction experiments, we formulate the chemical and crystallographic parameters which are fundamental in the formation and stabilization of new phases for use as functional materials. Below, a schematic of a chemical looping reaction involving a perovskite oxide and the the in-situ synchrotron diffraction with patterns collected every 6 seconds.

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Research area 4:: High capacity mesoporous metal oxides for toxic gas adsorption and degradation

Team members: Tianyu Li and Matthew Leonard

Chemical warfare agents (CWA) are an always prevalent threat for military and civilians. To ensure their protection, new materials need to be developed that can adsorb and degrade these CWAs. Current filters use an activated carbon to adsorb the CWA and ASZM-TEDA to degrade them. To increase reactivity, we make mesoporous metal oxides (MMO) using a variety of techniques including hard and soft templating to increase the surface area and overall reactivity. We started with making Fe2O3, TiO2 and CeO, but are also looking at perovskite structures LaBO3 (B = Mn, Fe, Co, Ni). These materials are also made with and in different structures (KIT-6, SBA-15, CMK-3, FDU-15 ect.) to determine how pore size and structure effect reactivity. This project is highly collaborative, working with the Kuklja group at UMD to do DFT calculations to understand the potential reactions occurring. The Zachariah group at UC Riverside to conduct DRIFTS studies and determine the kinetics and thermodynamic properties of the materials. Finally, the CCDC Chemical Biological Center to test these materials under live conditions.

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