title: Two-band and pauli-limiting effects on the upper critical field of 112-type iron pnictide superconductors.
abstract: The temperature dependence of upper critical field μ0Hc2of Ca0.83La0.17FeAs2and Ca0.8La0.2Fe0.98Co0.02As2single crystals are investigated by measuring the resistivity for the inter-plane (H//c) and in-plane (H//ab) directions in magnetic fields up to 60 T. It is found that μ0Hc2(T) of both crystals for H//c presents a sublinear temperature dependence with decreasing temperature, whereas the curve of μ0Hc2(T) for H//ab has a convex curvature and gradually tends to saturate at low temperatures. μ0Hc2(T) in both crystals deviates from the conventional Werthamer-Helfand-Hohenberg (WHH) theoretical model without considering spin paramagnetic effect for H//c and H//ab directions. Detailed analyses show that the behavior of μ0Hc2(T) in 112-type Iron-based superconductors (IBSs) is similar to that of most IBSs. Two-band model is required to fully reproduce the behavior of μ0Hc2(T) for H//c, while the effect of spin paramagnetic effect is responsible for the behavior of μ0Hc2(T) for H//ab.
authors.affiliation: Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
authors.forename: Xiangzhuo
authors.initials: X
authors.lastname: Xing
authors.affiliation: Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Wuhan National High Magnetic Field Center, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Wang
authors.affiliation: Wuhan National High Magnetic Field Center, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Zengwei
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhou
authors.affiliation: Advanced Functional Materials Lab and Department of Physics, Changshu Institute of Technology, Changshu 215500, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Qian
authors.affiliation: Advanced Functional Materials Lab and Department of Physics, Changshu Institute of Technology, Changshu 215500, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
authors.forename: Zhixiang
authors.initials: Z
authors.lastname: Shi