jmchen | nsrrcsrd

Jin-Ming Chen (陳錦明), Ph. D.

Research Scientist

Nano Science Group

Office: Room S115, R&D Building

E-Mail: jmchen@nsrrc.org.tw,

Tel: +886-35780281-7115

Education

1983-1987 Ph. D. in Chemistry, National Taiwan University

Employment

1989-1991 Visiting Scholar, Synchrotron Radiation Center, University of Wisconsin-Madison

Research Interest

Strongly correlated electronic systems such as 3d transition-metal oxides exhibit fascinating physical properties, such as metal-insulator transitions, colossal magnetoresistance, superconductivity, and multiferroicity. These unusual physical properties are related intimately to a delicate interplay between the crystal lattice, spin, charge, and orbital degrees of freedom. The application of pressure changes the inter-atomic distance and modify the electronic and the phononic energy spectra of materials. Pressure provides a powerful tool to manipulate the band structure, spin states, the lattice parameters and symmetry.

The cobaltates have attracted considerable attention in the scientific community because of their astonishing magnetic and transport properties, such as superconductivity, giant magnetoresistance, strong thermopower, as well as spin-blockade behavior. These properties are undoubtedly related to the spin state degree of freedom of the ions involved, i.e. the possibility of the Co3+ ions to be in a low spin (LS, S=0), high spin (HS, S=2) and even intermediate spin (IS, S=1) state. Yet, precisely this degree of freedom causes considerable confusion about which spin states or spin state changes are actually responsible for the properties.

Rare-earth intermetallic compounds of Ce, Yb, Sm and Eu have received much attention, because of their fascinating physical properties associated with the strong hybridization between conduction electrons and localized 4f electrons. Depending on the strength of the orbital hybridization, the properties of the rare-earth intermetallic compounds are characterized as having a heavy fermionic or intermediate valent electron state. Because the physical properties in intermediate valence compounds are very sensitive to the chemical and electronic environments around the rare-earth elements, the application of pressure changes the corresponding inter-atomic distance and modify the orbital hybridization Yb, Sm or Eu–based compounds.

We employed the resonant inelastic x-ray scattering (RIXS)-derived techniques, so called lifetime broadening suppressed x-ray absorption spectroscopy in the partial fluorescence yield. Combined with x-ray diffraction, XAS allows one to follow the evolution of the electronic states and structural parameters under high pressure. In electronic structure studies, the Kβ x-ray emission spectroscopy is now established as a local probe of the transition metal ion’s magnetic state. Changes in the Kβ emission lineshape are related to the variation of the local spin magnetic moment and can be used to follow the evolution of the metal ion’s magnetic state as a function of pressure. Variations in the valence, spin states, electronic structure, and local structure of strongly correlated electron materials under high pressure will be probed by combining high-pressure x-ray emission spectroscopy (XES), high-resolution spin-selective x-ray absorption spectroscopy (XAS) measured by partial fluorescence yield, resonant inelastic x-ray scattering (RIXS), high-pressure EXAFS, and high-pressure XRD measurements using synchrotron radiation.

The physical properties of thin films differ substantially from that of the bulk, due to reduced dimensionality and strain effect. Lattice mismatch can lead to structural modifications at the interface between the film and the substrate, strongly affecting the magnetic properties. The Curie temperature (Tc) , electronic structure, and the spin state of magnetic thin films are sensitive to the strains in relation to lattice mismatch, defect, and layer thickness. Strain effect can be utilized to tailor or optimize the magnetotransport properties of CMR thin films, although a comprehensive understanding of strain effect is still challenging. We investigated of the anisotropic bonding, orbital ordering, and the hybridization of the Mn 3d / Fe 3d states in YFexMn1-xO3 and YCrxMn1-xO3 using x-ray absorption spectroscopy (XAS), photoemission spectroscopy (PES), spin-selective x-ray absorption spectroscopy, resonant x-ray emission spectroscopy (RXES).

Selected Publication

1. A Complete High-to-low Spin State Transition of Trivalent Cobalt Ion in Octahedral Symmetry in SrCo0.5Ru0.5O3 δ, Jin-Ming Chen, Y. Y. Chin, M. Valldor*, Z. Hu, J. M. Lee, S. C. Haw, N. Hiraoka, H. Ishii, C. W. Pao, K. D. Tsuei, J. F. Lee, H. J. Lin, L. Y. Jang, A. Tanaka, C. T. Chen, and L. H. Tjeng. J. Am. Chem. Soc. 136, 1514 (2014)

2. Evolution of Spin and Valence States of (Pr0.7Sm0.3) 0.7Ca0.3CoO3 at High Temperature and High Pressur, Jin-Ming Chen*, J. M. Lee, S. C. Haw, S. A. Chen, V. Hardy, F. Guillou, S. W. Chen, C. Y. Kuo, C. W. Pao, J. F. Lee, N. Hiraoka, H. Ishii, K. D. Tsuei, and Z. Hu

Phys. Rev. B 90 , 035107 (2014).

3. Anisotropic Orbital occupation and Jahn-teller Distortion of Orthorhombic YMnO3 Epitaxial Films: a Combined Experimental and Theoretical Study on Polarization-dependent X-ray Absorption Spectroscopy, S.-C. Haw, J.-M. Lee, S.-A. Chen, K.-T. Lu, P.-A. Lin, C.-H. Lee, M.-T. Lee, T.-W. Pi, Z. Hu*, and Jin-Ming Chen*, J. Chem. Phys. 140 , 154503 (2014)

4. Atomic Distribution and Structural Evolution of Mesostructured PtRu Nanoparticles Electrodeposited on a Microemulsion Lyotropic Liquid-crystalline Template Probed Using EXAFS and XANES,. S.-A. Chen, Y.-C. Liang, K.-T. Lu*, C.-W. Pao, J.-F. Lee, T.-L. Lin, and Jin-Ming Chen*, Phys. Chem. Chem. Phys. 16, 3939 (2014)

5. Facile Electrochemical Synthesis of 3D Nano-architectured CuO Electrodes for High-performance Supercapacitors , M.-J. Deng*, C.-C. Wang, P.-J. Ho, C.-M. Lin, Jin-Ming Chen*, and K.-T. Lu*, J. Mater. Chem. A 2 , 12857 (2014)

6. Fabrication of Mn/Mn oxide core-shell electrodes with three-dimensionally ordered macroporous for high capacitance supercapacitors, Ming-Jay Deng*, Pei-Jung Ho, Cheng-Zhao Song , Shin-An Chen, Jyh-Fu Lee, Jin-Ming Chen*, Kueih-Tzu Lu*, Energy Environ. Sci. 6, 2178–2185 (2013).

7. Orbital Structure of FeTiO3 Ilmenite Investigated with Polarization-dependent X-ray Absorption Spectroscopy and Band Structure Calculations., S. W. Chen, M. J. Huang, P. A. Lin, H. T. Jeng, J. M. Lee, S. C. Haw, S. A. Chen, H. J. Lin, K. T. Lu, D. P. Chen, S. X. Dou, X. L. Wang*, and Jin-Ming Chen*, Appl. Phys. Lett. 102 , 042107 (2013)

8. Pressure-dependent Electronic Structures and Orbital Hybridization of Mn 3d States in Multiferroic BiMnO3: a Combined X-ray Absorption, X-ray Emission, and Resonant X-ray Emission Study, Jin-Ming Chen*, S. C. Haw, J. M. Lee, S. A. Chen, K. T. Lu, S. W. Chen, M. J. Deng, Y.-F. Liao, J. M. Lin, B. H. Chen, F. C. Chou, N. Hiraoka, H. Ishii, K. D. Tsuei, and E. Huang, Phys. Rev. B 86 , 045103 (2012)

9. Formation Process of Mesostructured PtRu nanoparticles Electrodeposited on a Microemulsion Lyotropic Liquid Crystalline Template, as Revealed by In-situ XRD, SAXS and XANES, Yu-Chia Liang, Yu-Wan Juan, Kueih-Tzu Lu, U-Ser Jeng*, Shin-An Chen, Wei-Tsung Chuang, Chun-Jen Su, Chin-Lung Liu, Chin-Wen Pao, Jyh-Fu Lee, Hwo-Shuenn Sheu, Jin-Ming Chen*, J. Phys. Chem. C 116, 26649 (2012)

10. Electronic structure and characteristics of Fe 3d valence states of Fe1.01Se superconductors under pressure probed by x-ray absorption spectroscopy and resonant x-ray emission spectroscopy, Jin-Ming Chen*, S. C. Haw, J. M. Lee, S. A. Chen, K. T. Lu, M. J. Deng, S. W. Chen, H. Ishii, N. Hiraoka, and K. D. Tsuei. J. Chem. Phys. 137, 244702 (2012).