Emeritus Prof Gillian Gehring OBE

Contact details

Photo of Gillian Gehring

Department of Physics and Astronomy
Hicks Building, Hounsfield Road, Sheffield, S3 7RH, UK
Tel(direct): +44 (0)114 2224299

email: g.gehring@sheffield.ac.uk

Introduction

For many applications the approximation that electrons move in a solid independently of each other and the movement of the ion cores is surprisingly good. Really interesting phenomena occur when this approximation breaks down: this includes magnetism, orbital ordering and superconductivity.

Most of my work is concerned with magnetism and orbital ordering particularly in oxides.

Some oxide semiconductors can become ferromagnetic when they are doped with magnetic ions. We study ZnO using transport and magneto-optics. I supervise both experimental and theoretical PhD students working to understand these phenomena. Part of this work was funded by a Leverhulme Emeritus Fellowship.

I also use my understanding of magnetic phase transitions to study phase transitions in other materials that can be modelled by a pseudo-spin formulation. This is currently done in collaboration with colleagues from the Department of Materials Science and Engineering, Professor Ungar and Dr X. Zeng. This collaboration has generated papers 1 and 2 in the list below and a current student, William Fall, is working on a related project.

I also have Royal Society funded collaboration with Moscow MISiS to study multiferroic manganites also active collaborations with groups in Saudi Arabia (KACST), and in China (Tsinghua University and the Academy of Science both in Beijing and Xanxi Normal University), Sweden (KTH) and also with the USA (Argonne National Laboratory)

Since I retired I became an Emeritus Professor and am devoting all my time to research and to some outreach activities.

Recent experimental publications include:

  1. Enhanced magnetic properties in ZnCoAlO caused by exchange-coupling to Co nanoparticles. Qi Feng, Wala Dizayee, Xiaoli Li, David S Score, James R Neal, Anthony J Behan, Abbas Mokhtari, Marzook S Alshammari, Mohammed S Al-Qahtani, Harry J Blythe, Roy W Chantrell, Steve M Heald, Xiao-Hong Xu, A Mark Fox and Gillian A Gehring New J. 5
  2. Advantageous use of metallic cobalt in the target for pulsed laser deposition of cobalt-doped ZnO films Minju Ying, Harry J. Blythe, Wala Dizayee, S.M. Heald, F.M. Gerriu, A.M. Fox and GA Gehring Appl. Phys. Lett. 109, 072403 (2016)
  3. The structure, optical and magnetic properties of arsenic implanted ZnO films prepared by molecular beam epitaxy Ying, Minju ; Wang, Shida; Duan, Tao; Liao, Bin; Zhang, Xu; Mei, Zengxia; Du, Xiaolong; Gerriu, F. M.; Fox, A. M; Gehring, G. A. Mat. Lett 171, 121 (2016)
  4. Magnetic Coupling of Dissimilar ZnO-Co Granular Films Through a ZnO Spacer Li, Xiaoli; Jia, Juan; Gao, Yan; Gehring, G. A; Xu, Xiaohong SPIN 5, 1540008 (2015)
  5. ZnO gap states investigated using magnetic circular dichroism Ying, Minju; Dizayee, Wala; Mei, Z. X.; Du, X. L.; Fox, A. Mark ; Gehring, Gillian A. J. Phys D –Appl. Phys 48, 255502 (2015)
  6. Electrical Manipulation of Orbital Occupancy and Magnetic Anisotropy in Manganites” Cui, Bin; Song, Cheng; Gehring, Gillian A.; Li, Fan; Wang, Guangyue; Chen, Chao; Peng, Jingjing; Mao, Haijun; Zeng, Fei; Pan, Feng Adv. Fn Mater. 25, 864-870 (2015)
  7. Morphology and magnetic properties of Fe3O4 nanodot arrays using template-assisted epitaxial growth Guan, Xiao-Fen et al. Nano Res Lett 10, 4 (2015)
  8. Magnetic properties of In2O3 containing Fe3O4 nanoparticles Alshammari, Marzook S.et al Phys Rev B 90, 144433 (2014)
  9. Structural and magnetotransport properties of ultrathin Co/ZnO and Co/ZnAlO films Quan, Zhi-Yong et al J. Appl. Phys. 115, 233908 (2014)
  10. Grain boundary ferromagnetism in vanadium-doped In2O3 thin films Feng, Qi et al Euro. Phys. Lett. 103, 67007 (2013)
  11. The role of Cu codoping on the Fe metal clustering and ferromagnetism in Fe-doped In2O3 films Jiang, Feng-Xian et al. Mater. Res. Bull. 48, 3178 (2013)
  12. Contrasting behavior of the structural and magnetic properties in Mn- and Fe-doped In2O3 films Feng, Qi et al. Appl. Phys. Mater. 1, 022107 (2013)
  13. Enhanced Room Temperature Magnetoresistance and Spin Injection from Metallic Cobalt in Co/ZnO and Co/ZnAlO Films Quan, Zhiyong et al. ACS Appl. Mater. & Interf. 5, 3607 (2013)
  14. Enhancement of the metal-insulator transition temperature in La0.7Ca0.3MnO3 film by magnetic nanodots Ma, Rong-Rong et al. Appl. Phys. Lett. 102, 072402 (2013)
  15. Magneto-optic studies of magnetic oxides GA Gehring, et al J. Mag. Mag. Mater 324 , 3422- 2012 (2012)

Recent theoretical papers include:

  1. Monte Carlo study of the ordering in a strongly frustrated liquid crystal S. George , C. Bentham, X. Zeng, G. Ungar and G.A. Gehring Phys Rev E 95, 062126 (2017)
  2. Magnetic Circular Dichroism Measurements of Thin Films Wala Dizayee, Minju Ying, A. Mark Fox, Gillian A. Gehring (2015) arXiv:1505.03458
  3. Monte Carlo simulations for Ising spins with spin greater than 1/2 applied to the square and triangular lattices with antiferromagnetic interactions and comparing results using Kawasaki and Glauber dynamics Jenny Poulton, Christopher Bentham, Stuart P. George, Gillian A. Gehring (2014) arXiv:1406.7816
  4. Complex multicolor tilings and critical phenomena in tetraphilic liquid crystals Xiangbing Zeng, Robert Kieffer, Benjamin Glettner, Constance Nürnberger, Feng Liu, Karsten Pelz, Marko Prehm, Ute Baumeister, Harald Hahn, Heinrich Lang, Gillian A. Gehring, Christa H. M. Weber, Jamie K. Hobbs, Carsten Tschierske and Goran Ungar Science 331, 1302 (2011)
  5. Carrier-mediated nonlocal ferromagnetic coupling between local magnetic polarons in diluted magnetic oxide semiconductors Shifei Qi, F. Jiang, J. Fan, SB Zhang, GA. Gehring, Zhenyu Zhang, XH Xu Phys Rev B 84, 205204 (2011)
  6. Landau theory of compressible magnets near a quantum critical point Gillian A Gehring and Mahrous R. Ahmed Proc MMM-Intermag J. Appl Phys 107, 09E125 (2010)
  7. Multiple Scattering Between Cylinders and a Schroeder Diffuser M.A. Pogson, D.M. Whittaker, G.A. Gehring, R.J. Hughes, J.A.S. Angus, T.J. Cox Acta Acustica United with Acustica 96, 292 (2010)
  8. Room temperature ferromagnetism in pristine MgO thin films C. Moyses Araujo, Mukes Kapilashrami, Xu Jun, O.D. Jayakumar, Sandeep Nagar, Yan Wu, Cecilia Arhammar, Borje Johansson, Lyubov Belova, Rajeev Ahuja, Gillian A Gehring, K.V. Rao Appl. Phys. Lett. 96, 232505 (2010)

Senior visitors

  • Minju Ying (November 2011-November 2012)
  • Xiaoli Li (September 2012 –August 2013)
  • Marzook Alshammari (September 2012- December 2012)
  • PhD students who graduated recently
  • Marzook Alshammari (January 2012)
  • Mohammed Alqahtani (April 2012)
  • Qi Feng (May 2013)

Current PhD students                  

  • Hasan Al-Bargi
  • Wala Dizayee                                                       
  • Aliaa Zaki
  • Ahmad Saeedi  
  • Fatma Gerriu                                   
  • William S. Fall

MSc and MPhys project students 2011-2016

  • Thomas Sexton
  • Nguyen Thanh Binh
  • Timothy Farrow                                              
  • Rania Alqurashi
  • Ahmed Taha
  • Christopher Bentham
  • Stuart George

Recently graduated PhD students

  • Qi Feng (May 2013)
  • Mohammed Alqahtani (April 2012)
  • Marzook Alshammari (January 2012)
  • Abbas Mokhtari (October 2008)
  • Anthony Behan (August 2008)

Current active overseas collaborations

  • Feng Pan and Cheng Song School of Materials Science & Engineering Tsinghua University Beijing China.
  • Marzook Alshammari The National Center of Nanotechnology,Materials Science Institute,KACST Saudi Arabia
  • Xiao-Hong Xu, Xiaoli Li, Zhi-Yong Quan, and Xiao-Fen Guan Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education and School of Chemistry and Materials Science, Shanxi Normal University China
  • Tao Xiang Institute of Physics Academy of Sciences Beijing China
  • Vladimir Chichkov MISiS Moscow Russia
  • KV Rao and Lyuba Belova Materials Science and Engineering, Royal Institute of Technology - KTH, Stockholm Sweden

Other Interests

Developing material to enthuse primary school children about science. The material is on the Institute of Physics web site, www.iop.org/pips (see Engaging the Public). I currently give presentations on

  • Solids, liquids and gases (using liquid nitrogen)
  • Growth of crystals using bubble rafts
  • Magnetism

I was the Principle Investigator on two EPSRC Partnership for Public Engagement Awards that generated the material on the PIPS web site.

I also give lectures on ‘Self Organisation’ to public audiences.

Encouraging women to study physics and maintain a high profile career: publications below:

  • "PhD’s are worth more for women" G A Gehring Physics World September 2001 http://physicsweb.org/articles/world/14/9/2
  • Letter to Physics World December 2001 G A Gehring "Unretiring Women"
  • "Mixing motherhood with science" G A Gehring Physics World March 2002 http://physicsweb.org/articles/world/15/3/3. This was reprinted by www.Science.Careers.org and is high on the google ‘hit list’. It still generates emails to GAG from around the world.
  • "Women physicists speak" G A Gehring and six other members of the UK team who attended the first IUPAP conference on women in Physics in Paris 2002.

Brief biographical details are on

https://en.wikipedia.org/wiki/Gillian_Gehring

and a brief summary of my academic interests are on my Departmental page

http://www.sheffield.ac.uk/physics/contacts/ggehring/index