実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）MLF Experimental Report

提出日 Date of Report
2013/03/25

課題番号 Project No.

装置責任者 Name of responsible person

2012B0165

Takashi Ohhara

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Magneticstructure

analysisonsinglecrystalneutronSENJU / BL18

diffractometer SENJU

実施日 Date of Experiment

実験責任者名 Name of principal investigator

2013/1/17 - 1/21

Takuro Kawsaki
所属 Affiliation
J-PARC center, Japan Atomic Energy Agency
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
1) TbCoGa5, 2.6 x 2 x 1.8 mm3, 30 mg, single crystal
2) HoCoGa5, 1 x 1 x 2 mm3, 30 mg, single crystal
3) DyCoGa5, 1.2 x 1.2 x 2 mm3, 35 mg, single crystal

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

The sample was attached to the vanadium stick with the diameter of  0.5 mm using an adhesive and it
mounted to the SENJU standard goniometer on the 4K-cryostat. The measurements were performed by thestandard procedures for SENJU.
The data reduction to obtain the integrated intensity of the reflections and visualization were performed using
the software STARGazer. The software JANA2006 was used to analyze the nuclear and magnetic structure ofthe samples.
Although three compounds used in this experiment have tetragonal HoCoGa5-type structure (so-called 115system), the magnetic structures of these compounds have an orthorhombic symmetry, and two magnetic
domains are coexisting in the antiferromagnetic phase. Therefore, these domains were treated as the twin
structure in the analyses. Though the analyses are not completed, fundamental procedures for a magneticstructure analysis on SENJU were demonstrated.
The result and status of the analysis for each compound are listed below.

12. 実験方法及び結果（つづき） Experimental method and results (continued)
1) TbCoGa5
The diffraction data were measured at 4.7 K, 10 K and 50 K for antiferromagnetic phase I, phase II andparamagnetic phase, respectively.
Magnetic superlattice reflections were observed at h/2, k, l/2 and the intensity was enhanced with thetemperature goes down.
Nuclear structure was refined using the fundamental reflections for the three temperatures. All the structuralparameters were converged to the reasonable value. The magnetic structure of the phase II was refined asshown in Fig. 1. The resultant reliability factor, R = 6.06 %, is a rather good value. The obtained magneticmoment of Tb3+ ion along c-axis, 8.56 B, well agreed with the previous reported value obtained from neutron
powder diffraction data. The analysis for phase I is now in progress.
2) HoCoGa5
The diffraction data were measured at 4.7 K, 8 K and 20 K for the antiferromagnetic phase, incommensurate
magnetic phase and paramagnetic phase, respectively.
Magnetic reflections were observed at h/2, k, l/2±0.287 and h/2, k, l/2 at 8 K and 4.7 K, respectively.
The analyses for HoCoGa5 are now in progress.
To obtain the integrated intensities of the reflections which appeared in an incommensurate phaseconveniently, the improvement of the data reduction software is required.
3) DyCoGa5
Experiment was not performed.

Fig. 1. Observed and calculated structure factor of TbCoGa5 at 10 K.

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