12-16 December 2016
Institut Laue-Langevin
Europe/Paris timezone

 

Monday 12 December

 

08:30 – 10:15 Registration

10:15 – 10:30 Workshop presentation (Juan Rodriguez-Carvajal, Grenoble, France)

10:30 – 11:30 History of magnetic structure determination (Laurent Chapon, Grenoble, France)

11:30 – 12:30 Fundamentals of magnetic neutron diffraction (Juan Rodriguez-Carvajal, Grenoble, France)

                Elementary description of magnetic structures, propagation vector formalism and calculation of magnetic structure factors.

 

12:30 – 14:00 Lunch

 

14:00 – 15:00 Introduction to the magnetic symmetry I. Magnetic space groups (J. Manuel Perez-Mato, Bilbao, Spain)

            Magnetic order as a symmetry break process. Magnetic space groups (MSGs) as subgroups of a paramagnetic symmetry group. Description of a commensurate magnetic structure under a MSG. Types of MSGs. OG vs. BNS description. “Standard” listings of MSGs. Non-standard settings and transformations. Symmetry constraints under a MSG. Consequences of a MSG symmetry: effective space group for non-magnetic degrees of freedom.

 15:00 – 16:00 Introduction to magnetic symmetry II. Representation analysis (Branton J. Campbell, Provo, USA)

           Irreducible representations (irreps) of space groups.  Order parameter directions and isotropy subgroups. Extension to magnetic gray groups: magnetic irreps. Magnetic order parameters and irreps.  The single irrep assumption (Landau theory).  Magnetic symmetry modes. Notation. Dependence of irrep labels on the choice of the unit cell basis. Star of an irrep. Complex irreps and physically irreducible representations. Survey of computer tools for magnetic irreps.

 

16:00 – 16:30 Coffee Break

 

16:30 – 17:30 Introduction to magnetic symmetry III. Magnetic space groups vs. irreps (J. Manuel Perez-Mato, Bilbao, Spain)

           Magnetic order parameter vs. spin wave amplitudes. Possible magnetic space groups (MSGs) for a single irrep spin ordering. Isotropy subgroups of an irrep: kernel and epikernels. k-maximal MSGs vs. irrep epikernels. Primary and secondary irreps. MSG restrictions on irrep basis modes. Case 1: no secondary irreps allowed. Case 2:  secondary irreps allowed; parameterization with a combined use of MSG symmetry and irrep basis modes

 

 17:30 – 18:00 The magCIF format (Branton J. Campbell, Provo, USA)

          Introduction to the magCIF format. Symmetry groups, magnetic moments, reference settings, constraints, BNS and OG(k) descriptions, parent data block. Focus on commensurate structures.

 

18:00 – 18:45 Tutorial: The Bilbao Crystallographic Server (BCS) (J. Manuel Perez-Mato, Bilbao, Spain)

            Overview of the magnetic section of the BCS. Database of MSGs and retrieval tools. Irreps and irrep analysis in the BCS. Tools to explore possible magnetic structures for a known propagation vector. Systematic search of possible single and multi-k structures. Visualization. Systematic absences. Symmetry-adapted crystal tensors.

 

18:45 - 21:00:  Welcome reception - Wine & Cheese buffet

 

Tuesday 13 December

 

9:00 – 10:30 Tutorial and Practical session: ISOCIF and ISODISTORT (Branton J. Campbell and Harold Stokes, Provo, USA)

            Order parameter directions and isotropy subgroups (kernel and epikernels) of an irrep in the commensurate case. Examples. Overview of ISODISTORT (methods 1-3) and ISOCIF for exploration of possible magnetic structures and their symmetry for one or more active irreps.  Output options.  Magnetic settings.

 

10:30 – 11:00 Coffee Break

 

11:00 – 12:30 Practical session: The Bilbao Crystallographic Server (J. Manuel Perez-Mato and Luis Elcoro, Bilbao, Spain) 

        MAXMAGN, k-SUBGROUPSMAG & MAGMODELIZE: Determine possible models for one or more propagation vectors

 

12:30 – 14:00  Lunch

 

14:00-16:00: Practical session: The Bilbao Crystallographic Server (J. Manuel Perez-Mato and Luis Elcoro, Bilbao, Spain)

        MAXMAGN, k-SUBGROUPSMAG & MAGMODELIZE: Explore possible models for one or more propagation vectors

        MVISUALIZE. Visualization with Jmol and with VESTA. Domains.

        MTENSOR. Macroscopic properties. Ferroic switching properties

 

16:00 – 16: 30 Coffee break

 

16:30 – 17:00 MAGNDATA: a collection of magnetic structures (towards a database of magnetic structures?) (Luis Elcoro, Bilbao, Spain)

 

17:00 – 18:30 Practical Session: ISODISTORT (Branton J. Campbell and Harold Stokes, Provo, USA)

        ISODISTORT.  Magnetic structure decomposition.  Magnetic mode amplitudes. Interfaces to structure-analysis packages. Preparing for magnetic structure refinement.

 

Wednesday 14 December

 

9:00 – 10:30 Superspace symmetry of incommensurate structures and its application to magnetic structures. Magnetic superspace groups (Vaclav Petricek, Prague, Czech Republic)

 

10:30 – 11:00 Coffee break

 

11:00 – 12:30 Tutorial and Practical Session: ISODISTORT (Branton J. Campbell and Harold Stokes, Provo, USA)

        ISODISTORT (method 2): Generate models for incommensurate magnetic modulations based on one or more active irreps.  Export incommensurate structure to magCIF.

 

12:30 – 14:00 Lunch

 

14:00 – 15:00 Tutorial: The program JANA and its magnetic option (Vaclav Petricek, Prague, Czech Republic)

        JANA: Refine a commensurate magnetic structure with JANA

 

15:00 – 16:00 Practical session: JANA  (Vaclav Petricek, Prague, Czech Republic)

        JANA: Refine an incommensurate magnetic structure

 

16:00 – 16:30 Coffee break

 

16:30 – 18:30 Practical session: JANA (Vaclav Petricek, Prague, Czech Republic)

        JANA: Refine an incommensurate magnetic structure

 

Thursday 15 December

 

9:00 – 10:30 FullProf for magnetic structures. New features (Juan Rodriguez-Carvajal, Grenoble, France)

 

10:30 – 11:00 Coffee break

 

11:00 – 12:30 Tutorial: Examples of different options for treating commensurate magnetic structures in FullProf (Juan Rodriguez-Carvajal, Grenoble, France)

 

12:30 – 14:00 Lunch

 

14:00 – 16:00: Practical session: FullProf (Juan Rodriguez-Carvajal and Oscar Fabelo, Grenoble, France)

        FullProf: Refine a commensurate magnetic structure

 

16:00 – 16:30 Coffee break

 

16:30 – 18:00 Practical session: FullProf (Juan Rodriguez-Carvajal and Oscar Fabelo, ILL, France)

        FullProf: Refine an incommensurate magnetic structure

 

19:00 Gala dinner

 

Friday 16 December

 

9:00 – 10:00 What computer tools or program extensions are yet needed? Suggestions for the future (Juan Rodriguez-Carvajal , Grenoble, France)

 

10:00 – 10:30 Coffee break

 

10:30 – 12:00 Round Table: how to deal with…?: domains in single crystals, domains-equivalent solutions, undistinguishable non-equivalent models, systematic absences, multi-k vs. single k structures,  etc.

 

12:00 – 12:30 Closing Session.

 

12:30 – 14:00 Lunch