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2009 MAGNETIC SYSTEMSStructural analysis with pulse-length exposures up to 30 Tesla at ID06, ESRFAs topical tests of the newly commissioned experimentalsetup at ID06, ESRF, synthetic powder samples of high T cNdFeAsO and of a natural atacamite, Cu 2 Cl(OH) 3 , havebeen measured in pulsed fields of up to 30 Tesla, usingpulse-simultaneous exposure times of less than 10 ms attemperatures down to 150 K (NdFeAsO) and 6 K (atacamite).temperatures and fields (Rp ∼ 0.06-0.07). The lower panelshows there is a measurable, and isotropic, effect on the inplanecell parameters with applied field. Preliminary analysisof cell parameter have given us direct information on thelattice strain in the sample. This taken with variable temperatureand field data should allow us to establish how the anycoupling parameters at the transition are field-affected. Theinternal parameters would give information on characteristicstructural features; such as bond lengths and perhapsmore critically, bond angle behaviour under variable fieldand temperature.Figure 114: Lattice distortion in NdFeAsO. The top panel shows,in blue, the variation in b/a, or the level of in-plane orthorhombicdistortion and in red the level of pseudo-tetragonal [2c/(a + b)]distortion at all temperatures and fields of 3 - 30 T . The lowerpanel indicates the effect on in-plane cell parameters at a fixedtemperature of 90 K, while augmenting pulse strength to 30 T.The green line shown indicates an increasing trend of 0.04 ÅT −1 .The two samples offer different challenges; not only froma point of view of disturbing their inherent magnetic propertiesat reduced temperature, but also from our ability toextract reliable structural information from powder sampleswith contrasting symmetries and structural complexities.For NdFeAsO, it is evident from figure 114 that lattice distortionmarkers show most variance in the range of measuredtemperatures between 120−205 K. Above and belowthese points there is little scatter, despite the same numberof data at each temperature and equivalent quality fits at allFigure 115: Rietveld refined, to R Bragg = 0.06, structure of atacamiteat T = 7 K, B = 30 T from 7 ms data collection on mar345image plate.The second study was designed to test the limits ofwhat structural analysis would be possible; using an altogethermore complicated orthorhombic structure, at basetemperatureof the cryostat and with our pulse-length limitedexposure times. Again here, the aim would be to determineinternal structural parameters to estimate if it wouldbe possible to extract any affect of high-field applicationon the frustration of the Kagomé-like lattice. We havebeen successful in refining atacamite to R Bragg of 0.06 atsub 10 K, with field strengths of up to 30 Tesla and pulselockedexposure times. Figure 115 shows the refined structure.Detailed analysis of the full dataset will determineif any field-induced frustration can give rise to a tractableresponse at these extreme conditions, though with experiencegained in setup, control and running this demandingmeasurement; we are confident that these methods offerconsiderable scope for future in situ diffraction research.F. DucT. Roth, C. Detlefs, W. A. Crichton (ESRF, Grenoble, France), S. Margadonna (University of Edinburgh, U.K.)85