Critical fields and the spontaneous vortex state in the weakly ferromagnetic superconductor RuSr2GdCu2O8

C. Y. Yang*, B. C. Chang, H. C. Ku, Y. Y. Hsu

*此作品的通信作者

研究成果: 雜誌貢獻期刊論文同行評審

15 引文 斯高帕斯(Scopus)

摘要

A spontaneous vortex state (SVS) between 30 and 56 K was observed for the weak-ferromagnetic superconductor RuSr2GdCu2O8 with the ferromagnetic Curie temperature TC=131K and the superconducting transition temperature Tc=56K. The low-field (±20G) super-conducting hysteresis loop indicates a narrow Meissner state region within the average lower critical field Bc1(T)=Bc1(0)[1-(TT0)2], with average Bc1ave(0)=12G and T0=30K. Full Meissner shielding signal in very low applied field indicates an ab plane Bc1ab(0)∼4G with an estimated anisotropic parameter γ∼7 for this layered system. The existence of a spontaneous vortex state between 30 and 56 K is the result of weak-ferromagnetic order with a net spontaneous magnetic moment of ∼0.1μBRu, which generates a weak magnetic dipole field around 10 G in the CuO2 bilayers. The upper critical field Bc2 varies linearly as (1-TTc) up to 7-T field. The vortex melting line Bm varies as (1-TTm)3.5 with melting transition temperature Tm=39K and a very broad vortex liquid region due to the coexistence and the interplay between superconductivity and weak-ferromagnetic order.

原文英語
文章編號174508
期刊Physical Review B - Condensed Matter and Materials Physics
72
發行號17
DOIs
出版狀態已發佈 - 2005 11月 1
對外發佈

ASJC Scopus subject areas

  • 電子、光磁材料
  • 凝聚態物理學

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