2017 Annual Report of the IUCr Commission on Magnetic Structures
At the IUCr Congress in Hyderabad in August 2017, Maxim Avdeev (Australia), Maria Teresa Fernandez-Diaz (France), Ovidiu Garlea (USA), Margarida Henriques (Czech Republic), Andrew Wills (UK), and Oksana Zaharko (Switzerland) were elected as new voting members of the commission, while Andrea Cornea (Italy), Daniel Litvin (USA), Vaclav Petricek (Czech Republic), Alexander Pirogov (Russia), Vladimir Pomjakushin (Switzerland), and Wieslawa Sikora (Poland) stepped down from the voting membership after many years of service. This rather large turnover came two terms after the formation of the commission (Madrid, 2011) as expected. The voting membership of the commission now includes Branton Campbell (Chair, USA), Maxim Avdeev (Australia), Maria Teresa Fernandez-Diaz (France), Ovidiu Garlea (USA), Margarida Henriques (Czech Republic), Manuel Perez-Mato (Spain), Juan Rodriguez-Carvajal (France), Taku Sato (Japan), Andrew Wills (UK), and Oksana Zaharko (Switzerland).
Mois Aroyo (Spain) continues to serve as a consultant to the commission, and is now joined by Danny Litvin (USA), Alexander Pirogov (Russia), and Wielslawa Sikora (Poland), who were previously voting members and who are helping to maintain continuity during a time of significant transition, as well as Javier Campo (Spain) who notably brings expertise in molecular magnetism to the commission. We express appreciation to Harold Stokes (USA), who has stepped down as a consultant to the commission, but who continues to be involved in its activities.
The commission held an online meeting on 14 Feb 2017, with Branton Campbell, Andrea Cornia, Danny Litvin, Manuel Perez-Mato, Vaclav Petricek, Alexander Pirogov, Vladimir Pomjakushin, Taku Sato participating. The primary focus of the meeting was promoting the upcoming congress in Hyderabad, which being an unusual location for the magnetic-structure community, required a special effort; we identified a significant list of regional and topical interests groups around the world to whom various commission members made contact via mailing lists and direct emails; we also decided to advertise to all members of the IUCr WDC who list magnetic or magnetism as profile keywords. The commission further discussed potential sponsorship or other supporting involvement in a variety of meetings planned for the next two years. On the technical side, we discussed the possibility of creating an international standard for magnetic space group symbols. An international standard could assist new researchers in understanding the symmetries present within and the physical property tensors allowed by each magnetic space group. Examples of avoidable misunderstandings in recent literature were highlighted. There is no general agreement about the form that such symbols might take. But we agreed to explore the issue in detail during the coming year.
Another online commission meeting was held on 25 Apr 2017 to discuss commission priorities and changes to the voting membership in the coming term. The key priorities are education/outreach, software/data infrastructure development, standards (e.g. magCIF), and diversity (gender, geographic, and topical).
In mid-July, Branton Campbell and Harold Stokes formulated an initial proposal for an international standard for magnetic space group symbols. This led to some lively debate. Many are enthusiastic about the potential for the proposal, and feel that the short-term trauma and confusion surrounding a new standard are outweighed by the long-term benefits, while others are either satisfied with the status quo (the historical OG and BNS symbols) or feel that the costs outweight the benefits. The critical issue to assess is how severe the deficiencies in the current systems really are. More discussion will follow.
The commission held an informal face-to-face meeting in Hyderabad on 26 Aug 2017, with Margarida Henriques, Juan Rodriguez Carvajal (represented by Oscar Fabelo), Taku Sato and Branton Campbell participating. Regarding education/outreach, we discussed (1) immediate efforts to organize an International School of Crystallography on magnetic structure in Erice in 2019, (2) the possibility of a four-day workshop somewhere in Asia, and (3) a satellite workshop at the IUCr Congress in Prague in 2020. Regarding software development, we discussed concrete plans to assist the developers of a variety of software packages to implement the new magCIF standard. Regarding standards, we discussed recent (reflection data) and pending (rotational analogoues) efforts of the magCIF working group to extend the magCIF dictionary, and the ongoing possibility of a new volume of the International Tables. We have already committed to prepare an introduction to magCIF in Volume G. Also in Hyderabad, the IUCr EC commended the commission for its activity and diversity, and formally suggested (1) active support of the next congress, (2) a commission-generated review article on magnetic crystallography, and (3) a journal article on the outcomes of the magCIF project.
We conducted a two-part online meeting on 10 Nov 2017 and 04 Dec 2017, in which all voting members and nearly all consultants of the commission participated. We identified nine upcoming international meetings or schools with opportunities to sponsor, organize, or otherwise support sessions on high-quality magnetic structure research. We also discussed potential avenues of funding for young-scientist bursary grants at the international school of crystallography in Erice in 2019. We briefly touched on the matter of an international standard for MSG symbols; it was suggested that a proper list of magnetic Hall-style symbols, which define the origin, may be a more pressing issue. Our efforts to assist software developers in adopting the magCIF standard have been quite active this year; notably, the Bilbao Crystallographic Server, including its database of magnetic structures, has been updated to the new standard. Perhaps we could encourage specific journals to require a magCIF file when submitting a magnetic structure. Juan reminded us that magnetic superspace groups have not been fully classified, and that this classification should be straightforward.
We also had a very engaging discussion of active feature developments in JANA, FullProf, TOPAS, GSAS2, the Bilbao Crystallographic Server, the ISOTROPY Suite, SARAH, and MODY. There’s a lot happening and an increasing need for programs to communicate with one another. For example, SARAH, FullProf, and JANA have been refining internally-generated symmetry-mode (representational analysis) models for years; FullProf can now import and directly refine magnetic symmetry-mode models from external tools like ISODISTORT; the user can self-program such a model in TOPAS. GSAS2 also has a beta feature for importing non-magnetic symmetry-mode models. The need to communicate such models between packages has reached a critical stage. Work on the representational-analysis CIF dictionary, which the commission has been discussing since 2011, will begin in the new year. Alexander suggested that when comparing experimentally undistinguisable models, the determination of the correct magnetic structure would be helped by a user-friendly software tool for calculating the exchange Hamiltonian of each model. And Manu recommended a general utility for manually creating both commensurate and incommensurate magCIF files. Oksana made a strong case for better support of single-crystal neutron diffraction in mainstream refinement packages; the capabilities exist, though more user-friendly interfaces and tutorial materials are badly needed; while the powder-diffraction community is much larger, though the single-crystal community needs support; improved support for polarized experiments is also justified. This led to an interesting general discussion of funding for single-crystal and powder software development and various administrative models. There are very few people in the world who understand the fine details of diffraction modeling well enough to do the programming. Large new facilities could play a leadership role in supporting this effort, both through long-term staff positions and though one-to-three year grant competitions in which the deliverables are specific software capabilities. Max asked how much the commission really knows about the need of software users, and suggested establishing formal channels for soliciting feedback and delivering responses (e.g. mailing list archives, wiki site, SLACK channel); workshop results are often repeated while an online response to a question persists. The commission supports a variety of scientific meetings each year through formal sponsorship, direct meeting organization, featured lecture presentations, workshop tutorials, the organization and chairing of conference sessions, and the presentation of lecture courses. Highlights from 2017 include the following:
- Shanghai International Crystallographic School: working with the Bilbao Crystallographic Server, Shanghai, China, 11-17 Jun 2017 (Mois Aroyo, Luis Elcoro).
- International Conference on Neutron Scattering, Daejeon, Korea, 9-13 Jul 2017 (Max Avdeev, Maria Teresa Fernandez-Diaz, Alexander Pirogov, Juan Rodriguez-Carvajal).
- ISODISTORT workshop on symmetry-mode analysis of nuclear and magnetic structures, 19 Aug 2017, Banaras Hindu University, Varanasi, India (Branton Campbell).
- XXIV IUCr Congress, Hyderabad, India, 21-28 Aug 2017. All commission members and consultants participated in the organization. Session chairs included Margarida Henriques, Taku Sato, and Branton Campbell.
- First International Conference on Intellectually Intensive Technologies in Energetics, Ekaterinburg, Russia, 20 Sep 2017 (Alexander Pirogov, invited lecture on “Structure and Magnetic Neutron Diffraction”).
- School on Neutron Diffraction Data Treatment using the FullProf Suite, Grenoble, France, 16-20 Oct 2017 (Maria-Teresa Fernandez-Diaz, Juan Rodriguez-Carvajal).
- Hokkaido University Graduate School of Engineering, intensive course on condensed matter research using neutron scattering, Sapporo, Japan, 7-9 Nov 2017 (Taku Sato).
- Ural Federal University, lecture course on magnetic neutron diffraction, Ekaterinburg, Russia, Nov-Dec 2017 (Alexander Pirogov).
Branton J. Campbell