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
課題番号 Project No.: 2015A0173
実験課題名

提出日 Date of Report
4 Oct. 2016
装置責任者 Name of Instrument scientist

Title of experiment: Novel high-energy spin

Shinichi Itohexcitation at sub-eV region in electron-doped high-Tc cuprate

装置名 Name of Instrument/（BL No.）

実験責任者名 Name of principal investigator: Fujita Masaki

HRC BL. 12

所属 Affiliation: Institute for Materials Research, Tohoku University

実施日 Date of Experiment
2015/6/15 – 2016/6/25

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.

As grown Pr1.4-xLa0.6CexCuO4 (x = 0.12)

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.

Experimental method : Inelastic neutron scattering
Measured temperature : 6 K
Incident neutron energies : 457, 122 and 24 meV
We performed inelastic neutron scattering measurements on as-grown Pr1.4-xLa0.6CexCuO4+δ (x =0.12) in order to clarify the electron-doping effect on the spin excitation in cuprate oxide. It isreported that the dispersion of high-energy spin excitation is robust against the hole-doping.
However, our recent resonant inelastic X-ray scattering and inelastic neutron scattering (INS)measurements on the electron-doped system revealed an evidence of elongation of excitation
spectrum along the energy direction, suggesting the electron-hole symmetry in the spin correlation[1]. Therefore, the detailed study of high-energy spin excitation in the electron-doped compoundby INS is required.
Figure 1 (a - c) shows the observed spectrum sliced at (a) 220 meV, (b) 60 meV and (c) 4 meV,respectively. We successfully observed the spin excitation spectrum up to 300 meV. The sharp
peak centered at the antiferromagnetic zone center (0.5, 0.5) can be seen in the low energy region,1

2. 実験方法及び結果（つづき） Experimental method and results (continued)

and the peak broadens with increasing energy transfer, which is consistent with the outwardly
dispersive spin-wave excitation with the strong dumping. We analyzed the constant-energy spectrawith assuming single Gaussian and evaluated the peak-width as a function of energy transfer.
Figure 2 shows the spin excitation spectrum and the evaluated peak-width in the full-with at thehalf-maximum is over-plotted by the horizontal bars. The peak-positions reported for the annealed
sample with comparable Ce concentration is also plotted by circles [2]. In the present study, weclarified the existence of high-energy excitation and the zone boundary energy exceeds 300 meV.
This result indicates that the spin excitation is indeed shift to high energy upon electron-doping.
The overall shape of excitation in as-grown and annealed systems is almost same in the measured
energy region suggest that the spectral shape is weakly affected by oxygen reduction, while thesuperconductivity emerges after annealing. The evaluation of absolute value of dynamicalsusceptibility is important to understand the relationship between magnetism andsuperconductivity in this system.

x10-918 (a)161412300.00.2(b)25(d) 400

0.4

0.60.81.020152.40.0(c) 0.2
2.01.6
1.20.80.00.2

S. D. Wilson et al

300

0.4

0.6

0.8

1.0

0.4
0.6
0.8(h, 0.5) (r. l. u)

1.0Energy (meV)-9

Intensityx10 (a. u.)x10-9[1] K. Ishii et al., Nature. Communication. 5, 3714 (2015).
[2] S. D. Wilson et al., Phys. Rev. Lett. 96, 157001 (2006)

200

100

00.00.5
1.0(h, 0.5) (r. l. u)

Fig 1 Spin excitation spectrum measured at 6 K and at (a) 220 meV, (b) 60 meV and (c) 4 meV. Redlines are the result of fitting with assuming single Gaussian and slope background. In the right figure,the horizontal bars indicate the peak-width (FWHM) evaluated from the analysis. The with circles are
the peak-positions reported for the annealed Pr1-xLaCexCuO4 (x = 0.12) [2].

2