Professional Background

I am a Staff Scientist in the Materials Science Division, Materials Dynamics and Kinetics Group, studying high-pressure/high-temperature (HPHT) structural behavior and equations of state (EOS) of energetic materials and detonation products. The unreacted EOS of energetic materials is important for thermo-chemical modeling and continuum-based simulations of physical and mechanical properties. I utilize diamond anvil cells (DACs) to produce HPHT conditions at X-ray synchrotron facilities such as the Advanced Photon Source (APS) and the Advanced Light Source (ALS) to perform HPHT diffraction measurements to determine lattice parameters and structural behavior at extreme conditions. Additionally, I use in-house LLNL laboratories equipped with micro-Raman systems to perform HP Raman spectroscopy and direct volume measurements via optical microscopy interferometry (OMI) techniques to understand the EOS of liquid polymers, amorphous materials, and other materials of interest.

My background is in HPHT structural, EOS, and electrical/thermal transport property measurements spanning a wide range of materials from alternative nuclear fuel materials, thermoelectric materials, energetic materials and intermetallic compounds of interest. During my time at Los Alamos National Laboratory in the Earth and Environmental Sciences Division as a Seaborg Postdoctoral Research Associate (2018–2020), I investigated the chemical speciation and coordination of aqueous uranyl solutions at HPHT conditions with X-ray absorption spectroscopy techniques and the high-pressure EOS of alternative nuclear fuels such as U₃Si_­5. As a Ph.D. candidate at the University of Nevada, Las Vegas (2012–2017), my dissertation explored electrical/thermal transport properties at HPHT conditions of chalcogenide thermoelectric materials by using and developing a specialized cell assembly for the Paris-Edinburgh type press.

Research Interests

• High-pressure and temperature structural, mechanical and electrical/thermal transport properties of materials
• High-pressure and temperature EOS of materials
• Identification of high-pressure/temperature phases of materials
• Developing and enhancing diagnostic tools to examine properties of materials in extreme environments

Ph.D. Physics, University of Nevada, Las Vegas, 2017

M.S. Physics, University of Nevada, Las Vegas, 2012

B.S. Physics, University of Nevada, Las Vegas, 2008

J.L. Baker, C. Park, C. Kenney-Benson, V. Kumar Sharma, V. Kanchana, G. Vaitheeswaran, C.J. Pickard, A. Cornelius, N. Velisavljevic, R.S. Kumar. Pressure-induced enhancement of thermoelectric figure of merit and structural phase transition in TiNiSn. J. Phys. Chem. Lett. 12, 1046-1051, (2021).

A. Kalintsev, A. Migdisov, C. Alcorn, J. Baker, J. Brugger, R.A. Mayanovic, N. Akram, X. Guo, H. Xu, H. Boukhalfa, F.A. Caporuscio, H. Viswanathan, C. Jove-Colon, Y. Wang, E. Matteo, R. Roback. Uranium carbonate complexes demonstrate drastic decrease in stability at elevated temperatures. Commun. Chem. 4, 120, (2021).

J.L. Baker, J.T. White, A. Chen, T. Ulrich, R. Roback, H. Xu. Heat capacity, entropy, formation energy and spin-fluctuation behavior of U₃Si₅ from 2.4 to 397.4 K. J. Nucl. Mater. 557, 153282, (2021).

J.L. Baker, G. Wang, T. Ulrich, J.T. White, E.R. Batista, P. Yang, R.C. Roback, C. Park, H. Xu. High-pressure structural behavior and elastic properties of U₃Si₅: A combined synchrotron XRD and DFT study. J. Nucl. Mater. 540, 152373, (2020).

T. Subramani, J. Baker, H. Xu, A. Navrotsky. Synthesis, characterization, and enthalpies of formation of uranium substituted zirconolites. ACS Earth Space Chem. 4, 1878-1887, (2020).

D. Dhakal, R. Mayanovic, J. Baker, H. Boukhalfa, H. Xu, C.J. Sun. Design of a containment apparatus for synchrotron XAS measurements of radioactive fluid samples under high temperatures and pressures. Rev. Sci. Instrum. 90, 083108, (2019).

J. Baker, R. Kumar, C. Park, N. Velisavljevic, A. Cornelius Compressibility and thermoelectric behavior of TiCoSb half-Heusler compound at high pressures. Intermetallics 95, 137–143, (2018).

J. Baker, R. Kumar, C. Park, C. Kenney-Benson, A. Cornelius, N. Velisavljevic. Giant Pressure-Induced Enhancement of Seebeck Coefficient and Thermoelectric Efficiency in SnTe. ChemPhysChem, 18, 3315-3319, (2017).

J. Baker, R. Kumar, C. Park, C. Kenney-Benson, A. Cornelius, N. Velisavljevic. High-pressure Seebeck coefficients and thermoelectric behaviors of Bi and PbTe measured using a Paris-Edinburgh cell. J. Synchrotron Radiat. 23, 1368-1378, (2016).

J. Baker, R. Kumar, D. Sneed, A. Connolly, Y. Zhang, N. Velisavljevic, J. Paladugu, M. Pravica, C. Chen, A. Cornelius, Y. Zhao. Pressure induced structural transitions in CuSbS₂ and CuSbSe₂ thermoelectric compounds. J. Alloys Compd. 643, 186 - 194, (2015).

2018–2020: Seaborg Postdoctoral Fellow, Los Alamos National Laboratory; Los Alamos, NM USA

2012–2013: Malcolm F. Nicol Fellowship, University of Nevada, Las Vegas; Las Vegas, NV USA