July 2018 - Ph.D. for Jamie Brambleby
Congratulations to Jamie Brambleby on successfully defending his Ph.D. thesis. His work was supervised by Paul Goddard.
Jamie's thesis is entitled Quantum magnetism in coordination polymers. The thesis can be downloaded from WRAP here.
September 2018 - Ali Julian leaves for Cornwall
It's goodbye and good luck to Ali Julian our Group Technician, who is leaving Warwick University to return to his family business in Cornwall. Everyone in the Group would like to thank Ali for all his hard work over the last three years and to wish him and the Julian family every success for their new life in Cornwall.
December 2017 - PhD for Daniel Brunt
Congratulations to Dan Brunt who has completed his doctorate. Dan, whose Ph.D. work was supervised by Oleg Petrenko, used in-house measurements and neutron scattering experiements performed at ISIS and the ILL to study the magnetic properties of some rare earth tetraborides.Dan's thesis which is entitled Magnetic properties of frustrated Shastry-Sutherland magnets; rare earth Tetraborides can be downloaded from his web page or from Warwick WRAP.
December 2017 - Award for the best paper published by a research fellow in the Physics Department in 2017
In recognition of the excellent contribution that postdocs make to the research in the Physics Department at the University of Warwick, the Head of Department, Prof. David Leadley, has initiated an award for the best paper published by a research fellow this year. Chris Patrick and Santosh Kumar from PRETAMAG have jointly won the first award for their paper “Rare-earth/transition-metal magnetic interactions in pristine and (Ni,Fe)-doped YCo5 and GdCo5” Phys.Rev.Materials 1, 02411 (2017). The paper was consider to be well-written and to convey clearly the outcomes of the joint theory-experimental activities. The interpretation of results and insight into the materials that this joint approach has enabled was particularly commended.
October 2017 - Welcome to 3 New Ph.D. Students
The Group welcomes 3 new Ph.D, students, Sam Holt, Bethany Hampshire, and Sam Curley. Sam Holt will be working with Geetha Balakrishnan on Skyrmionic materials. Beth will be working under the joint supervision of Don Paul (Warwick) and Aidy Hillier (ISIS-RAL) on the use of negative muons, studying at Warwick and at ISIS. Sam Curley will be working with Paul Goddard on an ERC project studying Quantum Materials under Extreme Conditions.
July - September 2017 URSS projects
Two Undergraduate Research Support Scheme (URSS) project students have joined the group over the summer. Oliver Rigby (3rd year Physics) is working with Martin Lees and Santosh Kumar on the physics of rare earth transition metal magnets as part of the PRETAMAG project. Stepan Marek (2nd year Physics) is working with Oleg Petrenko on SrRE2O4 frustrated magnetic materials.
July 2017 - Group Summer Meal
The Group held its summer meal at Seasons restaurant in Leamington Spa. The whole group took the chance to get together and to wish Saurabh Barua bon voyage, as he is leaving the Group soon when his post-doc comes to a close.
The meal came about due to the excellent organisation of Dan Brunt. Thanks Dan!
July - August 2017 - Three Visitors from Japan
Over the last month, Prof. Geetha Balakrishnan and the group have hosted three separate visits by Japanese scientists.
Dr. Kaya Kobayashi from Okayama University has been working with Dr Ales Stefancic growing some new superconducting single crystals.
Prof. Toshiro Takabatake from Hiroshima University, a world leading expert in crystal growth and especially heavy fermions, Kondo insulators, thermoelectrics and related materials, visited us to discuss joint projects that included a reciprocal visit by Dan Mayoh to Hiroshima in August.
Almost the whole group decamped to Abingdon to attend the annual Theoretical and Experimental Magnetism Meeting (TEMM 2017). The meeting was combined with IOP Magnetism TCM joint group symposium and the UK-Korea workshop on strongly correlated electron systems. It was a great chance to talk to old friends and colleagues and to make new contacts. Dan Brunt gave an invited talk at the TCM theory meeting.
Prof. Ray Osborn, who is based at Argonne National Laboratory in the USA visited us just before TEMM and gave a CMP seminar, while Dr. Sylvain Petit of LLB -CEA Saclay came back from Abingdon with us to visit our labs and discuss future projects.
Monica Hatnean Ciomaga and Geetha Balakrishnan both attended this year's APS March meeting in New Orleans. Part scientific meeting – part Mardi Gras!
January 2017 - Ph.D. for Joel Barker
Congratulations to Joel Barker on successfully defending his Ph.D. thesis. Joel, whose Ph.D. work was jointly supervised by Don Paul at Warwick and Aidy Hillier at ISIS-RAL, has been studying the physics of non-centrosymmetric superconductors with a particular emphasis on the use of muon spectroscopy.
Joel's thesis which is entitled Muon Studies of Unconventional Superconductors can be downloaded from his web page.
January 2017 - Welcome to Dr. Ales Stefancic and Marta Crisanti
We welcome Dr Ales Stefancic who has recently joined the Group as Post-Doctoral Research Assistant (PDRA) studying the physics of Skyrmionic materials. Ales will work here at Warwick as part of a larger EPSRC Programme Grant Skyrmionics: From Magnetic Excitations to Functioning Low-Energy Devices involving the Universities of Durham, Cambridge, Southampton, and Oxford. The work here at Warwick will be led by Prof. Geetha Balakrishnan.
We also welcome Marta Crisanti who joins us as a Warwick/ILL Ph.D. student working under the joint supervision of Don Paul (Warwick) and Robert Cubitt who works in the Large Scale Structures Group at the ILL. Marta will also be working on Skyrmionic materials, focussing on the use of small angle neutron scattering.
Oxides containing 5d ions, particularly Ir4+, offer possibilities for interesting spin-orbit and spin-lattice coupling effects. In these materials, the energy scales for spin-orbit interactions, Coulomb repulsion, and crystalline-electric fields can be very similar. Competition between these three energies can result in exotic magnetic states such as spin-orbit entanglement, extreme magnetic exchange anisotropy leading to, for example, a Kitaev spin liquid, and spin-orbit entangled Mott insulating behaviour.
Using experiments performed at the National High Magnetic Field Laboratory, a team from the USA, UK and South Korea (including Paul Goddard at Warwick) have observed extremely large coercive magnetic fields of up to 55 T in Sr3NiIrO6 and 52 T in Sr3CoIrO6, with switched magnetic moments of ≈ 1μB and 3μB per formula unit, respectively. Rather than the switching of magnetic domains, which is the cause of the coercive fields of traditional ferromagnets, the large hysteresis observed in our materials evolves out of a frustrated, antiferromagnetic ground state that incorporates an entangled spin-orbit state on the 5d ion.
Magnetic properties of Sr3NiIrO6 and Sr3CoIrO6: Magnetic hysteresis with coercive fields of up to 55 T, J. Singleton, J. W. Kim, C. V. Topping, A. Hansen, E.-D. Mun, S. Chikara, I. Lakis, S. Ghannadzadeh, P. Goddard, X. Luo, Y. S. Oh, S.-W. Cheong, and V. S. Zapf, Physical Review B 94, 224408 (2016).