@article{fang_zhang_zhang_jiang_vetter_lee_xu_sun_shen_2019, title={Nonvolatile Multilevel States in Multiferroic Tunnel Junctions}, volume={12}, ISSN={["2331-7019"]}, DOI={10.1103/PhysRevApplied.12.044049}, abstractNote={Manipulation of tunneling spin-polarized electrons via a ferroelectric interlayer sandwiched between two ferromagnetic electrodes, dubbed Multiferroic Tunnel Junctions (MFTJs), can be achieved not only by the magnetic alignments of two ferromagnets but also by the electric polarization of the ferroelectric interlayer, providing great opportunities for next-generation multi-state memory devices. Here we show that a La0.67Sr0.33MnO3 (LSMO)/PbZr0.2Ti0.8O3(PZT)/Co structured MFTJ device can exhibit multilevel resistance states in the presence of gradually reversed ferroelectric domains via tunneling electro-resistance and tunneling magnetoresistance, respectively. The nonvolatile ferroelectric control in the MFTJ can be attributed to separate contributions arising from two independent ferroelectric channels in the PZT interlayer with opposite polarization. Our study shows the dominant role of "mixed" ferroelectric states on achieving accumulative electrical modulation of multilevel resistance states in MFTJs, paving the way for multifunctional device applications.}, number={4}, journal={PHYSICAL REVIEW APPLIED}, author={Fang, Mei and Zhang, Sangjian and Zhang, Wenchao and Jiang, Lu and Vetter, Eric and Lee, Ho Nyung and Xu, Xiaoshan and Sun, Dali and Shen, Jian}, year={2019}, month={Oct} }
 @article{zhang_gardner_2005, title={CEARPGA II: A Monte Carlo simulation code for prompt-gamma-ray neutron activation analysis}, volume={151}, ISSN={["1943-748X"]}, DOI={10.13182/NSE05-A2556}, abstractNote={Abstract A Monte Carlo simulation code, CEARPGA II, has been developed to generate the complete set of library spectra that are required for the application of the Monte Carlo–Library Least-Squares approach in prompt-gamma-ray neutron activation analysis. Compared to the previous version, the CEARPGA I code, several important improvements have been made including eliminating the “big weight” problem by implementing the Analog Linear Interpolation technique, generating the appropriate detector response functions using improved simulation models that account for NaI detector nonlinearity and flat continua, generating the neutron activation backgrounds by directly sampling detector-activated gamma-ray energies, generating the natural background libraries by interpolating the energy-score tables, and tracking the annihilation gamma rays from the pair production interaction that occurs outside the detector. The coal sample spectrum calculated with the CEARPGA II code is benchmarked against those calculated from the CEARPGA I code, the MCNP code, and experimentally measured data.}, number={3}, journal={NUCLEAR SCIENCE AND ENGINEERING}, author={Zhang, WC and Gardner, RP}, year={2005}, month={Nov}, pages={361–373} }
 @article{gardner_zhang_metwally_2005, title={Status of software for PGNAA bulk analysis by the Monte Carlo - Library Least-Squares (MCLLS) approach}, volume={264}, ISSN={["0236-5731"]}, DOI={10.1007/s10967-005-0697-6}, number={1}, journal={JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY}, author={Gardner, RP and Zhang, W and Metwally, WA}, year={2005}, month={Apr}, pages={221–228} }
 @article{zhang_gardner_2004, title={The analog linear interpolation approach for Monte Carlo simulation of PGNAA: The CEARPGA code}, volume={213}, ISSN={["0168-583X"]}, DOI={10.1016/S0168-583X(03)01544-1}, abstractNote={The analog linear interpolation approach (ALI) has been developed and implemented to eliminate the big weight problem in the Monte Carlo simulation code CEARPGA. The CEARPGA code was previously developed to generate elemental library spectra for using the Monte Carlo – library least-squares (MCLLS) approach in prompt gamma-ray neutron activation analysis (PGNAA). In addition, some other improvements to this code have been introduced, including (1) adopting the latest photon cross-section data, (2) using an improved detector response function, (3) adding the neutron activation backgrounds, (4) generating the individual natural background libraries, (5) adding the tracking of annihilation photons from pair production interactions outside of the detector and (6) adopting a general geometry package. The simulated result from the new CEARPGA code is compared with those calculated from the previous CEARPGA code and the MCNP code and experimental data. The new CEARPGA code is found to give the best result.}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS}, author={Zhang, WC and Gardner, RP}, year={2004}, month={Jan}, pages={116–123} }