ᐇ㦂ሗ࿌᭩ᵝᘧ䠄୍⯡฼⏝ㄢ㢟䞉ᡂᯝබ㛤฼⏝䠅㻌䠄 䈜ᮏሗ࿌᭩䛿ⱥㄒ䛷グ㏙䛧䛶䛟䛰䛥䛔䚹䛯䛰䛧䚸⏘ᴗ฼⏝ㄢ㢟䛸䛧䛶᥇ᢥ䛥䜜䛶䛔䜛᪉䛿᪥ᮏㄒ䛷グ㏙䛧䛶䛔䛯䛰䛔䛶䜒⤖ᵓ䛷䛩䚹 䠅㻌Experimental Report㻌ᢎㄆ᪥ Date of Approval㻌 2016/6/22
ᢎㄆ⪅ Approver㻌 Ryoichi Kajimotoᥦฟ᪥ Date of Report㻌 2016/6/22

ㄢ㢟␒ྕ㻌 Project No.㻌⿦⨨㈐௵⪅ Name of Instrument scientist㻌㻞㻜㻝㻡㻭㻜㻜㻞㻥㻌㻾㻚㻌㻷㼍㼖㼕㼙㼛㼠㼛㻌㼍㼚㼐㻌㻹㻚㻌㻵㼟㼔㼕㼗㼍㼐㼛㻌ᐇ㦂ㄢ㢟ྡ㻌 Title of experiment㻌⿦⨨ྡ Name of Instrument/䠄BL No.䠅㻌

㻿㼑㼍㼞㼏㼔㻌㼒㼛㼞㻌㼒㼑㼞㼞㼛㼙㼍㼓㼚㼑㼠㼕㼏㻌㼒㼘㼡㼏㼠㼡㼍㼠㼕㼛㼚㼟㻌㼕㼚㻌㼜㻙㼣㼍㼢㼑㻌㼟㼡㼜㼑㼞㼏㼛㼚㼐㼡㼏㼠㼛㼞㻌 㻮㻸㻜㻝㻌㻿㼞㻞㻾㼡㻻㻠㻌

ᐇ᪋᪥ Date of Experiment㻌ᐇ㦂㈐௵⪅ྡ㻌 Name of principal investigator㻌㻥㻛㻢㻛㻞㻜㻝㻢㻌䇵㻌㻝㻡㻛㻢㻛㻞㻜㻝㻢㻌㻷㻚㻌㻵㼕㼐㼍㻌ᡤᒓ㻌 Affiliation㻌㻯㻾㻻㻿㻿㻌㻌ヨᩱ䚸ᐇ㦂᪉ἲ䚸฼⏝䛾⤖ᯝᚓ䜙䜜䛯୺䛺䝕䞊䝍䚸⪃ᐹ䚸⤖ㄽ➼䜢䚸グ㏙䛧䛶ୗ䛥䛔䚹䠄㐺ᐅ䚸ᅗ⾲ῧ௜䛾䛣䛸䠅㻌
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
㻝㻚㻌 ヨᩱ Name of sample(s) and chemical formula, or compositions including physical form.㻌
Co-aligned five single crystals Sr2RuO4 using 3He cryostat.
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㻞㻚㻌 ᐇ㦂᪉ἲཬ䜃⤖ᯝ㻌 䠄ᐇ㦂䛜䛖䜎䛟䛔䛛䛺䛛䛳䛯ሙྜ䚸䛭䛾⌮⏤䜢グ㏙䛧䛶䛟䛰䛥䛔䚹䠅㻌
Experimental method and results. If you failed to conduct experiment as planned, please describe reasons.
First of all, we would like to appreciate K. Kuwahara, S. Itoh, and K. Kaneko for 3He cryostat, goniometer,and motor driver, respectively. In addition, we also thank A. Nakao, K. Munakata, M. Ishikado, and Y. Inamura
for their help on 3He cryostat. Co-alignment of crystals was done by help from T. Moyoshi. Because we needspecial condition (T < 1 K), we could not perform our experiment without their help. We would also appreciate
MLF technical staffs. The vacuum pump at 4SEASONS was broken, and they replaced the pump very quickly
even though it happed on Sunday.
Despite many theoretical and experimental studies done since the discovery of superconductivity below Tc =1.5 K, the origin of the superconductivity in a strontium ruthenate, Sr2RuO4, is still under debate. The t2g
electrons of Ru4+ ions form three bands near the Fermi surface. The dxz and dyz orbitals form
quasi-one-dimensional α and β sheets while the dxy orbital forms a two-dimensional γ sheet. The former sheets
generate incommensurate (IC) magnetic fluctuations while the latter appears as ferromagnetic fluctuations. The 㻌㻞㻚㻌 ᐇ㦂᪉ἲཬ䜃⤖ᯝ䠄䛴䛵䛝䠅㻌 Experimental method and results (continued)
superconducting order parameter was proposed to be a p-wave state with a chiral px±ipy symmetry; the origin of
the p-wave superconductivity was originally thought to be ferromagnetic fluctuations due to the γ sheets. To
examine this scenario, several experiments were done, but they are not fully consistent. The imaginary part ofdynamic spin susceptibility obtained by inelastic neutron scattering measurements mainly shows the IC magnetic
fluctuations around Q = (0.3, 0.3, L), and their properties do not change below and above Tc. On the other hand, in17O-NMR measurements, 171/T1 shows ferromagnetic correlations. To investigate this issue, we performed

time-of-flight neutron scattering measurements on superconducting state in Sr2RuO4.
We used co-aligned five single crystals for neutron scattering measurements as shown in Fig. 1, which was put
in a copper sample can (Fig. 2). The can was attached to a 3He cryostat (heliox). The measurements were mainly
done at 0.3 and 2.8 K (Tc = 1.25 K). The Fermi chopper was rotated in 200 Hz frequency, giving rise to a set ofincident neutron energies of Ei = 7.38, 11.02, 18.20, 35.67, and 99.11 meV. T0 and two disk choppers wereoperated in the conventional condition. An oscillating radial collimator (2.5°vibration range with speed of 1° in 3
seconds using the “shift mode”) was installed after sample to reduce background. A set of slits was 45(w) – 50(h)– 40(w) – 45(h). Horizontal scattering plane was (HHL), and at 0.3 K, we rotate crystals by 100° from bothki//(001) and ki//(00-1) directions (200° in total).
As shown in Fig.3, in addition to IC fluctuations at Q = (±0.3, ±0.3, 1), we clearly observe additional signals
around the Γ point [(001) is not Γ point but “in-plane” Γ point], which is, we believe, the signature offerromagnetic fluctuations. Note that the peak positions do not locate exactly at Q = (0, 0, 1) instead at Q ~(±0.08, ±0.08, 1), which is consisted with the previous band calculation [see Fig. 6 bottom in the reference: N.
Kikugawa et al., Phys. Rev. B 70, 134520 (2004)]. Since we performed present experiment under special
condition as mentioned above, the background was considerably large. To clarify the origin of the peaks aroundthe Γ point, we are now treating the data as carefully as possible we can. We also plan to perform measurements
above Tc with a “low-background” condition, which will provide us the details on fine structure of theferromagnetic fluctuations.
㻌Fig. 1. Picuture of co-aligned Sr2RuO4 single crystals. Fig. 2. Sample can attached to the 3He_cryostat. Fig. 3. Constant energy cut along (HH1). Energy transfer, KK, and L were integrated
in [4, 5.5] meV, [-0.06, 0.06] rlu and [0.6, 1.4] rlu. Solid line is given by a Gaussian fitting.