Dr Jianli Wang Research Fellow BSc Shandong University, China, MSc, PhD Institute of Physics, Chinese Academy of Sciences School of Physical, Environmental and Mathematical Sciences UNSW @ ADFA Canberra   ACT   2600 AUSTRALIA Phone: +61 2 6268 9486 Fax: +61 2 6268 8786 Email: j.wang@adfa.edu.au Location: PEMS Sth, Room G29

Research Interests:

Advanced Materials

Bragg-UNSW@ADFA Research Fellow

Dr Jianli Wang’s position as Bragg- UNSW@ADFA Research Fellow (initially for a 3 year term) is part of this joint agreement. The Bragg Institute (www.ansto.gov.au/ bragg.html) is responsible for the development of neutron scattering instruments at the research reactor OPAL and aims to be an international leader in neutron beam and X-ray science. Jianli will work with colleagues here in PEMS and at the Bragg Institute on developmental and theoretical aspects of modern condensed matter science, particularly magnetism.

Current Research

Critical magnetic behavior and giant magneto-caloric effects in MnFeP_12-xAs_x–based compounds

Emeritus Prof. Stewart Campbell & Dr Jianli Wang

This project involves exploring the nature and relationship of the magnetic phase transition and magnetovolume effects by a detailed analysis of DC magnetization and ac susceptibility measurements at various DC biasing fields, linear thermal expansion measurements as well as variable temperature Mössbauer spectroscopy.

Magnetic phase transitions in RMn₂Ge₂-based compounds

Emeritus Prof. Stewart Campbell & Dr Jianli Wang

The aim of this project is to investigate the relationship between magnetic phase transitions and magnetostructural coupling by a variety of techniques (magnetisation; Mössbauer; neutron diffraction measurements from 20-350 K).

Magnetovolume effects in R₂Fe_17-xMn_x

Emeritus Prof. Stewart Campbell & Dr Jianli Wang

This project involves exploring the nature of the unexpected nonmonotonic composition dependence of the cell volume in R₂Fe_17-xMn_x and magnetic contribution to thermal expansion using variable temperature neutron diffraction and Mössbauer spectroscopy.

Nanostructured spinel ZnFe₂O₄ and NiFe₂O₄

Emeritus Prof. Stewart Campbell & Dr Jianli Wang

The aim of this project is to resolve details of the phases and reaction processes occurring during the high energy milling process and completely understand the structure-property relationships in nanoscale solids with respect to nanomagnetism.

Jianli Wang and Michael Hofmann analysing some of the neutron data hot off the GEM press at ISIS.	Stewart Campbell and Jianli Wang changing the sample on the GEM diffractometer, ISIS.

Recent achievements

Invar-like effect in Dy₂Fe_17-xMn_x

Emeritus Prof. Stewart Campbell & Dr Jianli Wang

A positive spontaneous magnetostriction has been found below the ordering temperature for Dy₂Fe_17-xMn_x compounds for x=0-5 and this invar-like effect evident around room temperature can account for the non-monotonic composition dependence of the lattice parameters of Dy₂Fe_17-xMn_x compounds at room temperature compared with other R₂Co_17-xMn_x and R₂Fe_{17- x}M_x systems M=Al, Ga, and Si.

Magnetic clustering in ZnFe₂O₄

Emeritus Prof. Stewart Campbell & Dr Jianli Wang

Nanostructured ZnFe₂O₄ of mean particle size d ~ 18(2) nm has been investigated over the temperature range 24–300 K using neutron polarization analysis. Separation of the spin flip and non-spin flip neutron scattering demonstrates that the diffuse peak which appears at (0.66, 0.66, 0) at 24 K is of magnetic origin and is elastic. Comparison of zero field and field cooled neutron depolarization measurements reveals the formation of oriented magnetic clusters at low temperatures.

Re-entrant ferromagnetism for PrMn_1.4Fe_0.6Ge₂

Emeritus Prof. Stewart Campbell & Dr Jianli Wang

Magnetic behaviour of PrMn_{2- x}Fe_xGe₂ compounds with x = 0-2 over the temperature range 4.2–350 K have been investigated. Substitution of Fe for Mn leads to a distinct decrease in the lattice constants and unit cell volume and re-entrant ferromagnetism was detected for PrMn_1.4Fe_0.6Ge₂ below TC(Pr) ~ 40 K. The temperature dependences of the hyperfine parameters exhibit changes at the phase transition temperatures determined from the magnetic measurements. An anisotropic thermal expansion occurs with interplanar antiferromagnetic coupling range for PrMn_1.2Fe_0.8Ge₂.

Synthesis of the novel rare earth intermetallic series RNi₂Mn

Emeritus Prof. Stewart Campbell & Dr Jianli Wang

Novel phase RNi₂Mn (R=Tb, Dy, Ho, Er) have been synthesised. Although the R to transition metal atom ratio is confirmed to be 1:3 using energy dispersive spectroscopy, the x-ray diffraction patterns are well described by a cubic Laves cell (space group Fd3m) with vacancies at the R sites. The ordering temperatures (TC =131 K, 94 K, 75 K, and 50 K for R=Tb, Dy, Ho and Er, respectively) are much higher than those of their corresponding RNi₂ and RMn₂ compounds.

Collaborators

• Drs S.J. Kennedy, M. Avdeev, A.J. Studer, D.H. Yu and Prof. M. James, Bragg Institute, ANSTO, Lucas Heights, NSW
• Prof. S.X. Dou and Dr R. Zeng, Institute of Superconductor and Electronic Materials, University of Wollongong
• Dr M. Hofmann, Technische Universität München, FRM-II, 85747 Garching, Germany
• Drs O. Tegus and E. Bruck, Van der Waales-Zeeman Institute, University of Amsterdam, The Netherlands
• Dr C. Marquina and Prof. M.R. Ibarra, Departmento de Física de la Materia Condensada, Universidad de Zaragoza, Spain
• Prof. G.H. Wu, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, P.R. China

Recent Publications

Journal - refereed

Wang, J. L. , Zeng R., Kim. J. H., Lu L. & Dou S. X., 2008, Effects of C substitution on the pinning mechanism of MgB₂, Physical Review B, 77(17), 174501-1 to 174501-7

Wang, J. L., Campbell, S. J., Marquina, C. & Ibarra, M. R., 2007, Magnetovolume effects in Dy₂Fe_17-xMn_x, Journal of Magnetism and Magnetic Materials, 310(2, part2), e569-e571.

Wang, J. L., Campbell, S. J., Tegus, O., Marquina, C. & Ibarra, M. R., 2007, Magneto effect and magnetic properties of Dy₂Fe_17-xMn_x, Physical Review B, 75(17), 174423-1-174423-9.

Wang, J. L., Campbell, S. J., Cadogan, J. M. & Edge, A. J. V., 2006, ⁵⁷Fe Mössbauer and magnetic studies of DyFe_12-xTa_x compounds, Hyperfine Interactions,168, 1097–1102, DOI 10.1007/ s10751-006-9408-0.

Wang, J. L., Campbell, S. J., Cadogan, J. M., Tegus, O., Studer, A. J. & Hofmann, M., 2006, Magnetic properties of PrMn_{2- x}Fe_xGe₂ - ⁵⁷Fe Mössbauer spectroscopy, Journal of Physics: Condensed Matter, 18(1), 189-204.

Wang, J., Marquina, C., Ibarra, M. R. & Wu, G. H., 2006, Structure and magnetic properties of RNi₂Mn compounds (R=Tb, Dy, Ho, and Er), Physical Review B, 73(9), 094436-1-094436-6.

Wang, J. L., Studer, A. J., Campbell, S. J., Hofmann, M. & Cadogan, J.M., 2006, Magnetic properties of PrMn_1.2Fe_0.8Ge₂, Physica B-Physics of Condensed Matter, 385-386, 326-329.

Conference Abstract

Wang, J., Campbell, S. J., Avdeev, M., Hofmann, M. & Hoelzel, M., 2007, Magnetic structures of PR_1-xY_xMn₂Ge₂ compounds, ANZIP & RACI 31st Annual Condensed Matter and Materials Meeting Conference Handbook, A. Barnhoorn et al. (eds), Charles Sturt University, Wagga Wagga, Canberra, Australia.

Wang, J., Campbell, S. J., Dou, S. X., Avdeev, M., Studer, A. J., Hofmann, M. & Hoelzel, M., 2007, Magnetic structures of Pr_0.5Y_0.5Mn₂Ge₂, 4th European Conference on Neutron Scattering Programme Presentations, A. Rennie et al. (eds), Lund, Sweden.

Wang, J. L., Kaczmarek, W. A., Campbell, S. J., Birou, P., Lawes, G. & James, M., 2006, Structural and magnetic properties of Y_1-xSr_xFeO₃, Thirtieth Annual Condensed Matter & Materials Meeting, Wagga Wagga, 7-10 February, 2006.

Grants

S. J. Campbell, K. Becker, I. Bergmann, V. Sepelak, M. Hofmann & J. L. Wang, Application for beam-time request on the OPAL neutron-beam facility, Structural and magnetic properties of mechano-synthesized NiO⁺Fe₂O₃ – nanostructured NiFe₂O₄, Bragg Institute, ANSTO, 2007, four days beam time awarded.

S. X. Dou, L. Z. Wang, S. J. Campbell, R. K. Zheng, X. L. Wang, J. Zou, X. Z. Liao, S. Li, Z. X. Cheng, J. Horvat, G. Peleckis, A. V. Pan, Y. Zhao, K. K. Konstantinov, R. A. Lewis, J. L. Wang, D. Q. Shi, Z. P. Guo, E. Pereloma, D. Wexler, S. H. Zhou, D. Li & R. J. Dippenaar, High field magnet for materials processing and characterisation, ARC LIEF E0882347, Australian Research Council, 2007:$340,000.

S. X. Dou, R. Zeng, J. L. Wang & D. H. Yu, Application for beam-time request on the OPAL neutron-beam facility, Magnetic structure of magnetocaloric compound Mn₃Sn₂, Bragg Institute, ANSTO, 2007, two days beam time awarded.

J. L. Wang, S. J. Campbell, S. X. Dou & R. Zeng, Application for beam-time request on the OPAL neutron-beam facility, Magnetovolume effects and magnetic structures of Ho₂Fe_17-xMn_x compounds, Bragg Institute, ANSTO, 2007, three days beam time awarded.

S. J. Campbell & J. L. Wang, Magnetic structure of the novel compound ErNi₂Mn, AINSE grant, Australian Institute of Nuclear Science and Engineering, 2006: $19,420.

S. X. Dou, C. Zhang, R. Ramer, J. G. Zhu, X. L. Wang, R. A. Lewis, S. J. Campbell, J. Horvat, S. Li, A. V. Pan, N. Valanoor, M. J. Qin, G. X. Wang, K. K. Konstantinov, J. L. Wang, Z. X. Cheng, D. Q. Shi, Y. Zhao, Y. G. Guo, Z. W. Lin & A. Dowd, Tesla physical property measurement system (PPMS), ARC LIEF LE0775559-16, Australian Research Council, 2006: $400,000.