実験報告書様式（一般利用課題・成果公開利用）
提出日 Date of Report
MLF Experimental Report
March 28, 2017

課題番号 Project No.

装置責任者 Name of responsible person

2016B0154

実験課題名 Title of experiment

Toru Ishigaki

Study of the anomalous magnetic ordering of a new cubic

iMATERIA/(BL20)

装置名 Name of Instrument/（BL No.）

compound Ce6Pd13Zn4

実験責任者名 Name of principal investigator

実施日 Date of Experiment
February 6-8, 2017

Eiichi Matsuoka

所属 Affiliation
Graduate School of Science, Kobe University

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.
Name of sample(s) and chemical formula, or compositions including physical form.

1. 試料

Ce6Pd13Zn4, powdered sample

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.

(1) Experimental method
Recently, we have focused on a new cubic compound Ce6Pd13Zn4. The magnetization, specific heat, andelectrical resistivity measurements revealed that Ce6Pd13Zn4 exhibits a second-order phase transition at Tt = 3.5
K and an additional resistivity anomaly at Tt' = 1.3 K. Although the decrease in Tt by magnetic field implies theoccurrence of an antiferromagnetic (AFM) order at Tt, the order parameter of the transition is still controversial
since the plateau appearing in the magnetic susceptibility and the appearance of an inflection of magnetization
below Tt are not typical for AFM transition. In this study, the neuron powder diffraction experiment ofCe6Pd13Zn4 has been performed using iMATERIA to determine the order parameter of the transition at Tt.
The powdered sample with the volume of 6 mmφ × 20 mm was packed in the Al cell designed for thisexperiment. This sample cell was set on the 1K Cryo and the sample temperature was monitored using athermometer mounted on the bottom of the Al cell. The diffraction patters were taken using the double framemode (12.5 Hz mode) at the temperature range between 0.69 and 7.0 K.

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2. 実験方法及び結果（つづき） Experimental method and results (continued)(2) Experimental results
Almost all of the Bragg peaks appearing in the diffraction pattern at 7.0 K (> Tt) can be indexed on the basisof the cubic Dy6Fe16O-type structure, although small peaks of unidentified impurity phases are discernible. At
2.5 K (< Tt), the other Bragg peaks that cannot be explained as the nuclear scattering appear at 5600 and 16300µs (time of flight). The intensities of these peaks increase at 0.69 K. These peaks are not superlattice peaks dueto the change in the crystal structure but the AFM peaks since no change in the peak angles and intensities ofnuclear peaks are observed between 0.69 and 7 K within the experimental precision.
The integrated intensity of the AFM peak at 16300 µs is almost temperature independent between 3.5 and 7
K. Below 3.5 K (= Tt), the integrated intensity increases gradually with decreasing temperature. We therefore
conclude that the second-order phase transition at Tt is due to the AFM order. It is noteworthy that the integrated
intensity shows a discontinuous increase below 1.3 K. This temperature corresponds to Tt' where the resistivity
shows an anomaly. Possible explanation of such discontinuous increase is a change in the magnetic structure atTt'.
Since the Ce atoms form a rectangular octahedron in the chemical unit cell of Ce6Pd13Zn4, it is expected that
the AFM structure is rather complex. Because of such complexity, the AFM peaks have not been indexed at thepresent stage. The determination of a magnetic structure is now in progress.

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