Dynamics of Self-Induced Quantum Vortices in Ferromagnetic Superconductor RuSr2YCU2O8

通过Ru-和Cu MKR的研究，我们提出了铜酸盐超导体RuSr_2YCu_2O_H（RuY 1212）中超导性和铁磁性共存的证据。在零磁场下观察到Ru-NMR信号的射频场大大增强，表明在T_M = 150 K的居里温度以下，有序RuO_2平面内存在铁磁（FM）成分。在低于超导起始温度Tc（onset）= 45 K时，有序RuO_2面和CuO_2面的核自旋-晶格弛豫速率（1/T_I）均显著降低，表明微观尺度上RuO_2面的超导能隙与FM组分共存。此外，在Tc<10>（零）~ 23 K电阻率变为零时，观察到了^（L/T_I）的一个尖峰，我们认为，RuY 1212中由FM分量涨落引起的自感涡旋运动导致了Tc（onset）和Tc（zero）之间的电阻率。我们还报道了五层化合物HgBa_2Ca_4Cu_5O_y（Hg-1245）（Tc =108 K）中超导性和反铁磁性的共存。它由两种CuO_2晶面组成，即三个内晶面（IP）和两个外晶面（OP）。Cu-NMR研究表明，最佳掺杂的OP在T_c=108 K发生超导转变，而三种欠掺杂IP在低于T_x = 60 K时发生反铁磁（AF）转变，Cu磁矩为0.3-0.4μ_&lt;K^+&gt;在IP处的AF自旋极化被发现在SC OP处诱导内场。在IP处观察到的金属行为给出了SC和AF有序参数共存于单一的CuO_2平面。

Frora Ru- and Cu MKR studies, we have presented evidence for coexistence of superconductivity and ferroraagnetism in a cuprate superconductor RuSr_2YCu_2O_H (RuY1212). The observation of a large enhancement of a radio-frequency field for the Ru-NMR signal at zero field reveals the existence of a ferromagnetic (FM) component in the ordered RuO_2 plane below a Curie temperature of T_M = 150 K. Just best below the onset temperature of superconductivity Tc(onset)= 45 K, a remarkable decrease of the nuclear spin-lattice relaxation rate 1/T_I was observed within the ordered RuO_2 plane as well as the CuO_2 plane revealing that the superconducting gap coexists with the FM component in the RuO_2 plane on a microscopic scale. In addition, from the the observation of a sharp pesk in ^<10>(L/T_I) at Tc(zero) 〜23 K where the resistivity becomes zero, we suggest that the motion of self-induced vortices originating from fluctuations of the FM component induces the resistivity between T c(onset) and T c(zero) in RuY1212.We alos have reported a coexistence of superconductivity and antiferromagnetism in five-layered compound HgBa_2Ca_4Cu_5O_y (Hg-1245) with T_c=108 K, which is composed of two types of CuO_2 planes in a unit cell, Three inner planes (IP) and twe outer planes (OP). The Cu-NMR study study has revealed that the optimally-doped OP undergoes a supercondcting (SC) transition at T_c=108 K, whereas the three underdoped IP's do an antiferromagnetic (AF) transition below T_x〜60 K with the Cu moments of 〜0.3-0.4μ_<K^+> The AF spin polarization at the IP is found to induce an internal fied at the SC OP. The observed metallic behavior at the IP gives the possibility that SC and AF order parameter coexist in a single CuO_2 plane.