Universal Superconducting Ground State in Nd_<1.85>Ce_<0.15>CuO_4 and Nd_2CuO_4
Universal Superconducting Ground State in Nd_<1.85>Ce_<0.15>CuO_4 and Nd_2CuO_4
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Nd_<1.85>Ce_<0.15>CuO_4 和 Nd_2CuO_4 的通用超导基态
DOI：
10.1143/jjap.51.010106
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发表时间：
2012
影响因子：
1.5
通讯作者：
M. Naito
中科院分区：
文献类型：
--
作者：
Y. Krockenberger;H. Yamamoto;M. Mitsuhashi;M. Naito
用分子束外延技术生长了超导Nd1.85Ce0.15CuO4（Tc = 24K）和Nd2CuO4（Tc = 25K）薄膜，研究了它们的磁输运和结构特性.无论替代水平如何，生长的薄膜都是绝缘体，并且在还原气氛下通过退火过程处理样品后诱导超导电性。虽然Ce4+掺杂样品的金属电导率较高，但其超导性能与未掺杂样品相当。Nd1.85Ce0.15CuO4和Nd2CuO4具有相似的上临界磁场和超导转变温度，表明电子的加入只影响超导态。因此，一个反铁磁莫特绝缘状态的外观完全取决于退火过程，而不是在电子掺杂或铈取代水平。
Superconducting Nd 1.85 Ce 0.15 CuO 4 (T c zero= 24 K) and Nd 2 CuO 4 (T c zero= 25 K) thin films have been grown by molecular beam epitaxy and their magneto-transport and structural properties have been investigated. The as-grown films are insulators irrespective of the substitution level, and superconductivity is induced after the samples are treated by an annealing process under reducing atmospheres. Though the metallic conductivity is higher in the Ce 4+ substituted sample, the superconducting properties are quite similar between Ce 4+ substituted and substitution-free samples. A similar upper critical magnetic field as well as a similar superconducting transition temperature of Nd 1.85 Ce 0.15 CuO 4 and Nd 2 CuO 4 shows that the addition of electrons merely influences the superconducting state. Consequently, the appearance of an antiferromagnetic Mott insulating state solely depends on the annealing process, not on the electron doping or cerium substitution level.