TY - JOUR
T1 - No evidence for "small-moment antiferromagnetism" under ambient pressure in URu2Si2
T2 - Single-crystal 29Si NMR study
AU - Takagi, Shigeru
AU - Ishihara, Shu
AU - Saitoh, Satoru
AU - Sasaki, Hiko Ichiro
AU - Tanida, Hiroshi
AU - Yokoyama, Makoto
AU - Amitsuka, Hiroshi
PY - 2007/3
Y1 - 2007/3
N2 - The still unidentified hidden order (HO) phase below T0 = 17.5 K in the heavy-electron superconductor URu2Si2 has been investigated by 29Si NMR on a single crystal under external magnetic field Hext ∥ c-axis and ambient pressure P. For a previously proposed model of the small-moment antiferromagnetism (SMAF), in which tiny-moment antiferromagnetism (AF) under ambient P is ascribed to spatially homogeneous AF with an ordered moment μSMAF = 0.02 -0.04 μB, splitting of the line would be expected on the basis of a scaling from the corresponding splitting in the P-induced AF. However, we observed at T = 4.5 K no splitting of the line. This clearly indicates that the SMAF model cannot describe the ambient-P properties. Below T0 down to ∼14 K, the 29Si NMR line shows additional broadening over the paramagnetic width. The additional contribution, however, disappears below ∼14 K, which indicates that the HO itself produces almost zero internal field at the 29Si site along the c-axis at low temperatures in the HO phase.
AB - The still unidentified hidden order (HO) phase below T0 = 17.5 K in the heavy-electron superconductor URu2Si2 has been investigated by 29Si NMR on a single crystal under external magnetic field Hext ∥ c-axis and ambient pressure P. For a previously proposed model of the small-moment antiferromagnetism (SMAF), in which tiny-moment antiferromagnetism (AF) under ambient P is ascribed to spatially homogeneous AF with an ordered moment μSMAF = 0.02 -0.04 μB, splitting of the line would be expected on the basis of a scaling from the corresponding splitting in the P-induced AF. However, we observed at T = 4.5 K no splitting of the line. This clearly indicates that the SMAF model cannot describe the ambient-P properties. Below T0 down to ∼14 K, the 29Si NMR line shows additional broadening over the paramagnetic width. The additional contribution, however, disappears below ∼14 K, which indicates that the HO itself produces almost zero internal field at the 29Si site along the c-axis at low temperatures in the HO phase.
KW - Antiferromagnetism
KW - Heavy electron
KW - NMR
KW - U compounds
KW - URuSi
UR - http://www.scopus.com/inward/record.url?scp=33947211217&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33947211217&partnerID=8YFLogxK
U2 - 10.1143/JPSJ.76.033708
DO - 10.1143/JPSJ.76.033708
M3 - Article
AN - SCOPUS:33947211217
VL - 76
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 3
M1 - 033708
ER -