TY - JOUR
T1 - Superconducting symmetries and magnetic responses of uranium heavy-fermion systems UBe13 and UPd2Al3
AU - Shimizu, Yusei
AU - Kittaka, Shunichiro
AU - Sakakibara, Toshiro
AU - Aoki, Dai
N1 - Funding Information:
The present work was done in collaboration with Y. Haga, H. Amitsuka, T. Yanagisawa, Y. Homma, K. Machida, Y. Tsutsumi, T. Nomoto, and H. Ikeda. The authors also thank Y. Yanase and K. Izawa for valuable discussions. The work has been supported in part by JSPS KAKENHI Grants No. 17K14328 .
PY - 2018/5/1
Y1 - 2018/5/1
N2 - Low-temperature thermodynamic investigation for UBe13 and UPd2Al3 were performed in order to gain insight into their unusual ground states of 5f electrons. Our heat-capacity data for the cubic UBe13 strongly suggest that nodal quasiparticles are absent and its superconducting (SC) gap is fully open over the Fermi surface. Moreover, two unusual thermodynamic anomalies are also observed in UBe13 at ∼ 3 T and ∼ 9 T; the lower-field anomaly is seen only in the SC mixed state by dc magnetization M(H) as well as heat-capacity C(H), while the higher-field anomaly appears for C(H) in the normal phase above the upper critical field. On the other hand, field-orientation dependence of the heat capacity in the hexagonal UPd2Al3 shows a significantly anisotropic behavior of C(H)∝H1/2, reflecting the nodal gap structure of this system. Our result strongly suggests the presence of a horizontal line node on the Fermi surface with heavy effective mass in UPd2Al3.
AB - Low-temperature thermodynamic investigation for UBe13 and UPd2Al3 were performed in order to gain insight into their unusual ground states of 5f electrons. Our heat-capacity data for the cubic UBe13 strongly suggest that nodal quasiparticles are absent and its superconducting (SC) gap is fully open over the Fermi surface. Moreover, two unusual thermodynamic anomalies are also observed in UBe13 at ∼ 3 T and ∼ 9 T; the lower-field anomaly is seen only in the SC mixed state by dc magnetization M(H) as well as heat-capacity C(H), while the higher-field anomaly appears for C(H) in the normal phase above the upper critical field. On the other hand, field-orientation dependence of the heat capacity in the hexagonal UPd2Al3 shows a significantly anisotropic behavior of C(H)∝H1/2, reflecting the nodal gap structure of this system. Our result strongly suggests the presence of a horizontal line node on the Fermi surface with heavy effective mass in UPd2Al3.
KW - Heavy-Fermion superconductivity
KW - Superconducting symmetry
KW - UBe
KW - UPdAl
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U2 - 10.1016/j.physb.2017.09.036
DO - 10.1016/j.physb.2017.09.036
M3 - Article
AN - SCOPUS:85032177155
VL - 536
SP - 553
EP - 557
JO - Physica B: Condensed Matter
JF - Physica B: Condensed Matter
SN - 0921-4526
ER -