Cameron Tracy

All Publications

• Cureton et al. Review of Swift Heavy Ion Irradiation Effects in CeO2 (vol 5, 19, 2021) QUANTUM BEAM SCIENCE Cureton, W. F., Tracy, C. L., Lang, M. 2021; 5 (3)

  View details for DOI 10.3390/qubs5030024

  View details for Web of Science ID 000700156600001

• Multi-scale investigation of heterogeneous swift heavy ion tracks in stannate pyrochlore JOURNAL OF MATERIALS CHEMISTRY A O'Quinn, E. C., Tracy, C. L., Cureton, W. F., Sachan, R., Neuefeind, J. C., Trautmann, C., Lang, M. K. 2021

  View details for DOI 10.1039/d1ta04924k

  View details for Web of Science ID 000680100100001

• Opportunities for US-Russian collaboration on the safe disposal of nuclear waste BULLETIN OF THE ATOMIC SCIENTISTS Tracy, C. L., Park, S., Plevaka, M., Bogdanova, E. 2021; 77 (3): 146-152

  View details for DOI 10.1080/00963402.2021.1912276

  View details for Web of Science ID 000649108800009

• Disorder in M(n+1)AX(n) phases at the atomic scale NATURE COMMUNICATIONS Wang, C., Yang, T., Tracy, C. L., Lu, C., Zhang, H., Hu, Y., Wang, L., Qi, L., Gu, L., Huang, Q., Zhang, J., Wang, J., Xue, J., Ewing, R. C., Wang, Y. 2019; 10

  View details for DOI 10.1038/s41467-019-08588-1

  View details for Web of Science ID 000458008700001

• Disorder in Mn+1AXn phases at the atomic scale. Nature communications Wang, C., Yang, T., Tracy, C. L., Lu, C., Zhang, H., Hu, Y., Wang, L., Qi, L., Gu, L., Huang, Q., Zhang, J., Wang, J., Xue, J., Ewing, R. C., Wang, Y. 2019; 10 (1): 622

  Abstract

  Atomic disordering in materials alters their physical and chemical properties and can subsequently affect their performance. In complex ceramic materials, it is a challenge to understand the nature of structural disordering, due to the difficulty of direct, atomic-scale experimental observations. Here we report the direct imaging of ion irradiation-induced antisite defects in Mn+1AXn phases using double CS-corrected scanning transmission electron microscopy and provide compelling evidence of order-to-disorder phase transformations, overturning the conventional view that irradiation causes phase decomposition to binary fcc-structured Mn+1Xn. With the formation of uniformly distributed cation antisite defects and the rearrangement of X anions, disordered solid solution gamma-(Mn+1A)Xn phases are formed at low ion fluences, followed by gradual transitions to solid solution fcc-structured (Mn+1A)Xn phases. This study provides a comprehensive understanding of the order-to-disorder transformations in Mn+1AXn phases and proposes a method for the synthesis of new solid solution (Mn+1A)Xn phases by tailoring the disorder.

  View details for PubMedID 30733461

• Measurement of UO2 surface oxidation using grazing-incidence x-ray diffraction: Implications for nuclear forensics JOURNAL OF NUCLEAR MATERIALS Tracy, C. L., Chen, C., Park, S., Davisson, M., Ewing, R. C. 2018; 502: 68–75

  View details for DOI 10.1016/j.jnucmat.2018.01.052

  View details for Web of Science ID 000427676700008

• Review of recent experimental results on the behavior of actinide-bearing oxides and related materials in extreme environments PROGRESS IN NUCLEAR ENERGY Tracy, C. L., Lang, M., Zhang, F., Park, S., Palomares, R. I., Ewing, R. C. 2018; 104: 342–58

  View details for DOI 10.1016/j.pnucene.2016.09.012

  View details for Web of Science ID 000424177700033

• Radiation-induced disorder in compressed lanthanide zirconates PHYSICAL CHEMISTRY CHEMICAL PHYSICS Park, S., Tracy, C. L., Zhang, F., Park, C., Trautmann, C., Tkachev, S. N., Lang, M., Maoah, W. L., Ewing, R. C. 2018; 20 (9): 6187–97

  Abstract

  The effects of swift heavy ion irradiation-induced disordering on the behavior of lanthanide zirconate compounds (Ln2Zr2O7 where Ln = Sm, Er, or Nd) at high pressures are investigated. After irradiation with 2.2 GeV 197Au ions, the initial ordered pyrochlore structure (Fd3[combining macron]m) transformed to a defect-fluorite structure (Fm3[combining macron]m) in Sm2Zr2O7 and Nd2Zr2O7. For irradiated Er2Zr2O7, which has a defect-fluorite structure, ion irradiation induces local disordering by introducing Frenkel defects despite retention of the initial structure. When subjected to high pressures (>29 GPa) in the absence of irradiation, all of these compounds transform to a cotunnite-like (Pnma) phase, followed by sluggish amorphization with further compression. However, if these compounds are irradiated prior to compression, the high pressure cotunnite-like phase is not formed. Rather, they transform directly from their post-irradiation defect-fluorite structure to an amorphous structure upon compression (>25 GPa). Defects and disordering induced by swift heavy ion irradiation alter the transformation pathways by raising the energetic barriers for the transformation to the high pressure cotunnite-like phase, rendering it inaccessible. As a result, the high pressure stability field of the amorphous phase is expanded to lower pressures when irradiation is coupled with compression. The responses of materials in the lanthanide zirconate system to irradiation and compression, both individually and in tandem, are strongly influenced by the specific lanthanide composition, which governs the defect energetics at extreme conditions.

  View details for PubMedID 29431823

• A(2)TiO(5) (A = Dy, Gd, Er, Yb) at High Pressure INORGANIC CHEMISTRY Park, S., Rittman, D. R., Tracy, C. L., Chapman, K. W., Zhang, F., Park, C., Tkachev, S. N., O'Quinn, E., Shamblin, J., Lang, M., Mao, W. L., Ewing, R. C. 2018; 57 (4): 2269–77

  Abstract

  The structural evolution of lanthanide A2TiO5 (A = Dy, Gd, Yb, Er) at high pressure is investigated using synchrotron X-ray diffraction. The effects of A-site cation size and of the initial structure are systematically examined by varying the composition of the isostructural lanthanide titanates and the structure of dysprosium titanate polymorphs (orthorhombic, hexagonal, and cubic), respectively. All samples undergo irreversible high-pressure phase transformations, but with different onset pressures depending on the initial structure. While each individual phase exhibits different phase transformation histories, all samples commonly experience a sluggish transformation to a defect cotunnite-like (Pnma) phase for a certain pressure range. Orthorhombic Dy2TiO5 and Gd2TiO5 form P21am at pressures below 9 GPa and Pnma above 13 GPa. Pyrochlore-type Dy2TiO5 and Er2TiO5 as well as defect-fluorite-type Yb2TiO5 form Pnma at ∼21 GPa, followed by Im3̅m. Hexagonal Dy2TiO5 forms Pnma directly, although a small amount of remnants of hexagonal Dy2TiO5 is observed even at the highest pressure (∼55 GPa) reached, indicating kinetic limitations in the hexagonal Dy2TiO5 phase transformations at high pressure. Decompression of these materials leads to different metastable phases. Most interestingly, a high-pressure cubic X-type phase (Im3̅m) is confirmed using high-resolution transmission electron microscopy on recovered pyrochlore-type Er2TiO5. The kinetic constraints on this metastable phase yield a mixture of both the X-type phase and amorphous domains upon pressure release. This is the first observation of an X-type phase for an A2BO5 composition at high pressure.

  View details for PubMedID 29420026

• Initial stages of ion beam-induced phase transformations in Gd2O3 and Lu2O3 APPLIED PHYSICS LETTERS Chen, C., Tracy, C. L., Wang, C., Lang, M., Ewing, R. C. 2018; 112 (7)

  View details for DOI 10.1063/1.5013018

  View details for Web of Science ID 000425493600051

• Role of the X and n factors in ion-irradiation induced phase transformations of M(n+1)AX(n) phases ACTA MATERIALIA Wang, C., Yang, T., Tracy, C. L., Xiao, J., Liu, S., Fang, Y., Yan, Z., Ge, W., Xue, J., Zhang, J., Wang, J., Huang, Q., Ewing, R. C., Wang, Y. 2018; 144: 432–46

  View details for DOI 10.1016/j.actamat.2017.11.008

  View details for Web of Science ID 000424067100040

• Similar local order in disordered fluorite and aperiodic pyrochlore structures ACTA MATERIALIA Shamblin, J., Tracy, C. L., Palomares, R. I., O'Quinn, E. C., Ewing, R. C., Neuefeind, J., Feygenson, M., Behrens, J., Trautmann, C., Lang, M. 2018; 144: 60–67

  View details for DOI 10.1016/j.actamat.2017.10.044

  View details for Web of Science ID 000424067100007

• Swift-heavy ion irradiation response and annealing behavior of A(2)TiO(5) (A = Nd, Gd, and Yb) JOURNAL OF SOLID STATE CHEMISTRY Park, S., Tracy, C. L., Zhang, F., Palomares, R. I., Park, C., Trautmann, C., Lang, M., Mao, W. L., Ewing, R. C. 2018; 258: 108–16

  View details for DOI 10.1016/j.jssc.2017.09.028

  View details for Web of Science ID 000423650400015

• Phase transformation pathways of ultrafast-laser-irradiated Ln(2)O(3) (Ln = Er-Lu) PHYSICAL REVIEW B Rittman, D. R., Tracy, C. L., Chen, C., Solomon, J. M., Asta, M., Mao, W. L., Yalisove, S. M., Ewing, R. C. 2018; 97 (2)

  View details for DOI 10.1103/PhysRevB.97.024104

  View details for Web of Science ID 000419704200004

• Lanthanide stannate pyrochlores (Ln(2)Sn(2)O(7); Ln = Nd, Gd, Er) at high pressure JOURNAL OF PHYSICS-CONDENSED MATTER Turner, K. M., Tracy, C. L., Mao, W. L., Ewing, R. C. 2017; 29 (50)

  View details for DOI 10.1088/1361-648X/aa9960

  View details for Web of Science ID 000425265700001

• Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln  =  Nd, Gd, Er) at high pressure. Journal of physics. Condensed matter : an Institute of Physics journal Turner, K. M., Tracy, C. L., Mao, W. L., Ewing, R. C. 2017; 29 (50): 504005

  Abstract

  Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln  =  Nd, Gd, and Er) were investigated in situ to 50 GPa in order to determine their structural response to compression and compare their response to that of lanthanide titanate, zirconate, and hafnate pyrochlores. The cation radius ratio of A3+/B4+ in pyrochlore oxides (A2B2O7) is thought to be the dominant feature that influences their response on compression. The ionic radius of Sn4+ is intermediate to that of Ti4+, Zr4+, and Hf4+, but the 〈Sn-O〉 bond in stannate pyrochlore is more covalent than the 〈B-O〉 bonds in titanates, zirconate, and hafnates. In stannates, based on in situ Raman spectroscopy, pyrochlore cation and anion sublattices begin to disorder with the onset of compression, first measured at 0.3 GPa. The extent of sublattice disorder versus pressure is greater in stannates with a smaller Ln3+ cation. Stannate pyrochlores (Fd-3m) begin a sluggish transformation to an orthorhombic, cotunnite-like structure at ~28 GPa; similar transitions have been observed in titanate, zirconate, and hafnate pyrochlores at varying pressures (18-40 GPa) with cation radius ratio. The extent of the phase transition versus pressure varies directly with the size of the Ln3+ cation. Post-decompression from ~50 GPa, Er2Sn2O7 and Gd2Sn2O7 adopt a pyrochlore structure, rather than the multi-scale defect-fluorite  +  weberite-type structure adopted by Nd2Sn2O7 that is characteristic of titanate, zirconate, and hafnate pyrochlores under similar conditions. Like pyrochlore titanates, zirconates, and hafnates, the bulk modulus, B 0, of stannates varies linearly and inversely with cation radius ratio from 1 1 1 GPa (Nd2Sn2O7) to 251 GPa (Er2Sn2O7). The trends of bulk moduli in stannates in this study are in excellent agreement with previous experimental studies on stannates and suggest that the size of the Ln3+ cation is the primary determining factor of B 0. Additionally, when normalized to r A/r B, the bulk moduli of stannates are comparable to those of zirconates and hafnates, which vary from titanates. Our results suggest that the cation radius ratio strongly influences the bulk moduli of stannates, as well as their overall compression response.

  View details for DOI 10.1088/1361-648X/aa9960

  View details for PubMedID 29176046

• Lanthanide stannate pyrochlores (Ln₂Sn₂O₇; Ln = Nd, Gd, Er) at high pressure. Journal of physics. Condensed matter : an Institute of Physics journal Turner, K. M., Tracy, C. L., Mao, W. L., Ewing, R. C. 2017

  Abstract

  Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln=Nd, Gd, and Er) were investigated in situ to 50 GPa in order to determine their structural response to compression and compare it to that of lanthanide titanate, zirconate, and hafnate pyrochlores. The cation radius ratio of A3+/B4+ in pyrochlore oxides (A2B2O7) is thought to be the dominant property that influences their compression response. The ionic radius of Sn4+ is intermediate to that of Ti4+, Zr4+, and Hf4+, but the <Sn-O> bond in stannate pyrochlore is more covalent than the <B-O> bonds in titanates, zirconate, and hafnates. In stannates, the pyrochlore cation and anion sublattices begin to disorder at 0.3 GPa. The extent of sublattice disorder vs. pressure is greater in stannates with a smaller Ln3+ cation. Stannate pyrochlores (Fd-3m) begin a sluggish transformation to a cotunnite-like structure (Pnma) at ~28 GPa; similar transitions have been observed in titanate, zirconate, and hafnate pyrochlore at varying pressures with cation radius ratio. The extent of the phase transition vs. pressure varies directly with the size of the Ln3+ cation. Post-decompression from ~50 GPa, Er2Sn2O7 and Gd2Sn2O7 adopt a pyrochlore structure, rather than the multiscale defect-fluorite + weberite structure adopted by Nd2Sn2O7 that is characteristic of titanate, zirconate, and hafnate pyrochlore treated to similar conditions. Like pyrochlore titanates, zirconates, and hafnates, the bulk modulus, B0, of stannates varies linearly and inversely with cation radius ratio. The trends of bulk moduli in stannates in this study are in excellent agreement with previous experimental studies on stannates, and suggest that the size of the Ln3+ cation is a primary determining factor of B0. Additionally, when normalized to rA/rB, the bulk moduli of stannates are comparable to those of zirconates and hafnates, which vary from titanates. Our results suggest that the cation radius ratio strongly influences the bulk moduli of stannates as well as their overall compression response.

  View details for DOI 10.1088/1361-648X/aa9960

  View details for PubMedID 29120343

• Thermal defect annealing of swift heavy ion irradiated ThO2 NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Palomares, R. I., Tracy, C. L., Neuefeind, J., Ewing, R. C., Trautmann, C., Lang, M. 2017; 405: 15-21

  View details for DOI 10.1016/j.nimb.2017.05.007

  View details for Web of Science ID 000404501200003

• Structure and bulk modulus of Ln-doped UO2 (Ln = La, Nd) at high pressure JOURNAL OF NUCLEAR MATERIALS Rittman, D. R., Park, S., Tracy, C. L., Zhang, L., Palomares, R. I., Lang, M., Navrotsky, A., Mao, W. L., Ewing, R. C. 2017; 490: 28-33

  View details for DOI 10.1016/j.jnucmat.2017.04.007

  View details for Web of Science ID 000403132300003

• Pressure-induced structural modifications of rare-earth hafnate pyrochlore. Journal of physics. Condensed matter : an Institute of Physics journal Turner, K. M., Rittman, D. R., Heymach, R. A., Tracy, C. L., Turner, M. L., Fuentes, A. F., Mao, W. L., Ewing, R. C. 2017; 29 (25): 255401-?

  Abstract

  Complex oxides with the pyrochlore (A2B2O7) and defect-fluorite ((A,B)4O7) structure-types undergo structural transformations under high-pressure. Rare-earth hafnates (A2Hf2O7) form the pyrochlore structure for A  =  La-Tb and the defect-fluorite structure for A  =  Dy-Lu. High-pressure transformations in A2Hf2O7 pyrochlore (A  =  Sm, Eu, Gd) and defect-fluorite (A  =  Dy, Y, Yb) were investigated up to ~50 GPa and characterized by in situ Raman spectroscopy and synchrotron x-ray diffraction (XRD). Raman spectra at ambient pressure revealed that all compositions, including the defect-fluorites, have some pyrochlore-type short-range order. In situ high-pressure synchrotron XRD showed that all of the rare earth hafnates investigated undergo a pressure-induced phase transition to a cotunnite-like (orthorhombic) structure that begins between 18 and 25 GPa. The phase transition to the cotunnite-like structure is not complete at 50 GPa, and upon release of pressure, the hafnates transform to defect-fluorite with an amorphous component. For all compositions, in situ Raman spectroscopy showed that disordering occurs gradually with increasing pressure. Pyrochlore-structured hafnates retain their short-range order to a higher pressure (30 GPa vs.  <10 GPa) than defect-fluorite-structured hafnates. Rare earth hafnates quenched from 50 GPa show Raman spectra consistent with weberite-type structures, as also reported for irradiated rare-earth stannates. The second-order Birch-Murnaghan equation of state fit gives a bulk modulus of ~250 GPa for hafnates with the pyrochlore structure, and ~400 GPa for hafnates with the defect-fluorite structure. Dy2Hf2O7 is intermediate in its response, with some pyrochlore-type ordering, based on Raman spectroscopy and the equation of state, with a bulk modulus of ~300 GPa. As predicted based on the similar ionic radius of Zr(4+) and Hf(4+), rare-earth hafnates show similar behavior to that reported for rare earth zirconates at high pressure.

  View details for DOI 10.1088/1361-648X/aa7148

  View details for PubMedID 28541929

• Defect accumulation in swift heavy ion-irradiated CeO2 and ThO2 JOURNAL OF MATERIALS CHEMISTRY A Palomares, R. I., Shamblin, J., Tracy, C. L., Neuefeind, J., Ewing, R. C., Trautmann, C., Lang, M. 2017; 5 (24): 12193–201

  View details for DOI 10.1039/c7ta02640d

  View details for Web of Science ID 000403664800026

• High pressure synthesis of a hexagonal close-packed phase of the high-entropy alloy CrMnFeCoNi NATURE COMMUNICATIONS Tracy, C. L., Park, S., Rittman, D. R., Zinkle, S. J., Bei, H., Lang, M., Ewing, R. C., Mao, W. L. 2017; 8

  Abstract

  High-entropy alloys, near-equiatomic solid solutions of five or more elements, represent a new strategy for the design of materials with properties superior to those of conventional alloys. However, their phase space remains constrained, with transition metal high-entropy alloys exhibiting only face- or body-centered cubic structures. Here, we report the high-pressure synthesis of a hexagonal close-packed phase of the prototypical high-entropy alloy CrMnFeCoNi. This martensitic transformation begins at 14 GPa and is attributed to suppression of the local magnetic moments, destabilizing the initial fcc structure. Similar to fcc-to-hcp transformations in Al and the noble gases, the transformation is sluggish, occurring over a range of >40 GPa. However, the behaviour of CrMnFeCoNi is unique in that the hcp phase is retained following decompression to ambient pressure, yielding metastable fcc-hcp mixtures. This demonstrates a means of tuning the structures and properties of high-entropy alloys in a manner not achievable by conventional processing techniques.

  View details for DOI 10.1038/ncomms15634

  View details for Web of Science ID 000401966000001

  View details for PubMedID 28541277

• Structural response of titanate pyrochlores to swift heavy ion irradiation ACTA MATERIALIA Shamblin, J., Tracy, C. L., Ewing, R. C., Zhang, F., Li, W., Trautmann, C., Lang, M. 2016; 117: 207-215

  View details for DOI 10.1016/j.actamat.2016.07.017

  View details for Web of Science ID 000383005300020

• Role of composition, bond covalency, and short-range order in the disordering of stannate pyrochlores by swift heavy ion irradiation PHYSICAL REVIEW B Tracy, C. L., Shamblin, J., Park, S., Zhang, F., Trautmann, C., Lang, M., Ewing, R. C. 2016; 94 (6)

  View details for DOI 10.1103/PhysRevB.94.064102

  View details for Web of Science ID 000380950400002

• Stability of fluorite-type La2Ce2O7 under extreme conditions JOURNAL OF ALLOYS AND COMPOUNDS Zhang, F. X., Tracy, C. L., Lang, M., Ewing, R. C. 2016; 674: 168-173

  View details for DOI 10.1016/j.jallcom.2016.03.002

  View details for Web of Science ID 000373612500024

• Anisotropic expansion and amorphization of Ga2O3 irradiated with 946 MeV Au ions NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Tracy, C. L., Lang, M., Severin, D., Bender, M., Trautmann, C., Ewing, R. C. 2016; 374: 40-44

  View details for DOI 10.1016/j.nimb.2015.08.059

  View details for Web of Science ID 000375819500009

• Probing disorder in isometric pyrochlore and related complex oxides NATURE MATERIALS Shamblin, J., Feygenson, M., Neuefeind, J., Tracy, C. L., Zhang, F., Finkeldei, S., Bosbach, D., Zhou, H., Ewing, R. C., Lang, M. 2016; 15 (5): 507-?

  Abstract

  There has been an increased focus on understanding the energetics of structures with unconventional ordering (for example, correlated disorder that is heterogeneous across different length scales). In particular, compounds with the isometric pyrochlore structure, A2B2O7, can adopt a disordered, isometric fluorite-type structure, (A, B)4O7, under extreme conditions. Despite the importance of the disordering process there exists only a limited understanding of the role of local ordering on the energy landscape. We have used neutron total scattering to show that disordered fluorite (induced intrinsically by composition/stoichiometry or at far-from-equilibrium conditions produced by high-energy radiation) consists of a local orthorhombic structural unit that is repeated by a pseudo-translational symmetry, such that orthorhombic and isometric arrays coexist at different length scales. We also show that inversion in isometric spinel occurs by a similar process. This insight provides a new basis for understanding order-to-disorder transformations important for applications such as plutonium immobilization, fast ion conduction, and thermal barrier coatings.

  View details for DOI 10.1038/NMAT4581

  View details for Web of Science ID 000374763500010

  View details for PubMedID 26928636

• Reassess New Mexico's nuclear-waste repository NATURE Tracy, C. L., Dustin, M. K., Ewing, R. C. 2016; 529 (7585): 149-151

  View details for Web of Science ID 000368015700013

  View details for PubMedID 26762442

• Pressure-induced phase transitions of beta-type pyrochlore CsTaWO6 RSC ADVANCES Zhang, F. X., Tracy, C. L., Shamblin, J., Palomares, R. I., Lang, M., Park, S., PARK, C., Tkachev, S., Ewing, R. C. 2016; 6 (97): 94287-94293

  View details for DOI 10.1039/c6ra11185h

  View details for Web of Science ID 000385632400001

• Phase transformations in Ln(2)O(3) materials irradiated with swift heavy ions PHYSICAL REVIEW B Tracy, C. L., Lang, M., Zhang, F., Trautmann, C., Ewing, R. C. 2015; 92 (17)

  View details for DOI 10.1103/PhysRevB.92.174101

  View details for Web of Science ID 000364013100001

• Response of Gd2Ti2O7 and La2Ti2O7 to swift-heavy ion irradiation and annealing ACTA MATERIALIA Park, S., Lang, M., Tracy, C. L., Zhang, J., Zhang, F., Trautmann, C., Rodriguez, M. D., Kluth, P., Ewing, R. C. 2015; 93: 1-11

  View details for DOI 10.1016/j.actamat.2015.04.010

  View details for Web of Science ID 000356207500001

• In situ defect annealing of swift heavy ion irradiated CeO2 and ThO2 using synchrotron X-ray diffraction and a hydrothermal diamond anvil cell JOURNAL OF APPLIED CRYSTALLOGRAPHY Palomares, R. I., Tracy, C. L., Zhang, F., Park, C., Popov, D., Trautmann, C., Ewing, R. C., Lang, M. 2015; 48: 711-717

  View details for DOI 10.1107/S160057671500477X

  View details for Web of Science ID 000355562000011

• Characterization of ion-induced radiation effects in nuclear materials using synchrotron x-ray techniques JOURNAL OF MATERIALS RESEARCH Lang, M., Tracy, C. L., Palomares, R. I., Zhang, F., Severin, D., Bender, M., Trautmann, C., Park, C., Prakapenka, V. B., Skuratov, V. A., Ewing, R. C. 2015; 30 (9): 1366-1379

  View details for DOI 10.1557/jmr.2015.6

  View details for Web of Science ID 000355283500016

• Ultrafast laser and swift heavy ion irradiation: Response of Gd2O3 and ZrO2 to intense electronic excitation APPLIED PHYSICS LETTERS Rittman, D. R., Tracy, C. L., Cusick, A. B., Abere, M. J., Torralva, B., Ewing, R. C., Yalisove, S. M. 2015; 106 (17)

  View details for DOI 10.1063/1.4919720

  View details for Web of Science ID 000353839100029

• Redox response of actinide materials to highly ionizing radiation NATURE COMMUNICATIONS Tracy, C. L., Lang, M., Pray, J. M., Zhang, F., Popov, D., Park, C., Trautmann, C., Bender, M., Severin, D., Skuratov, V. A., Ewing, R. C. 2015; 6

  Abstract

  Energetic radiation can cause dramatic changes in the physical and chemical properties of actinide materials, degrading their performance in fission-based energy systems. As advanced nuclear fuels and wasteforms are developed, fundamental understanding of the processes controlling radiation damage accumulation is necessary. Here we report oxidation state reduction of actinide and analogue elements caused by high-energy, heavy ion irradiation and demonstrate coupling of this redox behaviour with structural modifications. ThO2, in which thorium is stable only in a tetravalent state, exhibits damage accumulation processes distinct from those of multivalent cation compounds CeO2 (Ce(3+) and Ce(4+)) and UO3 (U(4+), U(5+) and U(6+)). The radiation tolerance of these materials depends on the efficiency of this redox reaction, such that damage can be inhibited by altering grain size and cation valence variability. Thus, the redox behaviour of actinide materials is important for the design of nuclear fuels and the prediction of their performance.

  View details for DOI 10.1038/ncomms7133

  View details for Web of Science ID 000348832300004

  View details for PubMedID 25626111

• Incorporation of uranium in pyrochlore oxides and pressure-induced phase transitions JOURNAL OF SOLID STATE CHEMISTRY Zhang, F. X., Lang, M., Tracy, C., Ewing, R. C., Gregg, D. J., Lumpkin, G. R. 2014; 219: 49-54

  View details for DOI 10.1016/j.jssc.2014.07.011

  View details for Web of Science ID 000342336100007

• Swift heavy ion track formation in Gd2Zr2-xTixO7 pyrochlore: Effect of electronic energy loss NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Lang, M., Toulemonde, M., Zhang, J., Zhang, F., Tracy, C. L., Lian, J., Wang, Z., Weber, W. J., Severin, D., Bender, M., Trautmann, C., Ewing, R. C. 2014; 336: 102-115

  View details for DOI 10.1016/j.nimb.2014.06.019

  View details for Web of Science ID 000341550200015

• Swift heavy ion irradiation-induced amorphization of La2Ti2O7 NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Park, S., Lang, M., Tracy, C. L., Zhang, J., Zhang, F., Trautmann, C., Kluth, P., Rodriguez, M. D., Ewing, R. C. 2014; 326: 145-149

  View details for DOI 10.1016/j.nimb.2013.10.088

  View details for Web of Science ID 000335631300035

• Defect accumulation in ThO2 irradiated with swift heavy ions NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Tracy, C. L., Pray, J. M., Lang, M., Popov, D., Park, C., Trautmann, C., Ewing, R. C. 2014; 326: 169-173

  View details for DOI 10.1016/j.nimb.2013.08.070

  View details for Web of Science ID 000335631300040

• Swift heavy ion-induced phase transformation in Gd2O3 NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Lang, M., Zhang, F., Zhang, J., Tracy, C. L., Cusick, A. B., VonEhr, J., Chen, Z., Trautmann, C., Ewing, R. C. 2014; 326: 121-125

  View details for DOI 10.1016/j.nimb.2013.10.073

  View details for Web of Science ID 000335631300030

• Structural response of A(2)TiO(5) (A = La, Nd, Sm, Gd) to swift heavy ion irradiation ACTA MATERIALIA Tracy, C. L., Lang, M., Zhang, J., Zhang, F., Wang, Z., Ewing, R. C. 2012; 60 (11): 4477-4486

  View details for DOI 10.1016/j.actamat.2012.05.005

  View details for Web of Science ID 000306621300012