NMR Evidence of Antiferromagnetic Spin Fluctuations in Nd_(0.85)Sr_(0.15)NiO_(2)  

作　　者：Yi Cui Cong Li Qing Li Xiyu Zhu Ze Hu Yi-feng Yang Jinshan Zhang Rong Yu Hai-Hu Wen Weiqiang Yu 崔祎;李聪;李庆;祝熙宇;胡泽;杨义峰;张金珊;俞榕;闻海虎;于伟强(Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials&Micro-nano Devices,Renmin University of China,Beijing 100872,China;National Laboratory of Solid State Microstructures and Department of Physics,Center for Superconducting Physics and Materials,Collaborative Innovation Center for Advanced Microstructures,Nanjing University,Nanjing 210093,China;Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;Mathematics and Physics Department,North China Electric Power University,Beijing 102206,China)

机构地区：[1]Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials&Micro-nano Devices,Renmin University of China,Beijing 100872,China [2]National Laboratory of Solid State Microstructures and Department of Physics,Center for Superconducting Physics and Materials,Collaborative Innovation Center for Advanced Microstructures,Nanjing University,Nanjing 210093,China [3]Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [4]Mathematics and Physics Department,North China Electric Power University,Beijing 102206,China

出　　处：《Chinese Physics Letters》2021年第6期61-66,共6页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Grant Nos.51872328,11674392,11774401,and A0402/11927809);the National Key R&D Program of China(Grant Nos.2016YFA0300504 and 2016YFA0300401);China Postdoctoral Science Foundation(Grant No.2020M680797);the Fundamental Research Funds for the Central Universities;the Research Funds of Renmin University of China(Grant Nos.18XNLG24,20XNLG19,and 21XNLG18)。

摘　　要：Despite the recent discovery of superconductivity in Nd_(1-x)Sr_(x)NiO_(2) thin films,the absence of superconductivity and antiferromagnetism in their bulk materials remains a puzzle.Here we report the 1H NMR measurements on powdered Nd0.85Sr0.15NiO2 samples by taking advantage of the enriched proton concentration after hydrogen annealing.We find a large full width at half maximum of the spectrum,which keeps increasing with decreasing the temperature T and exhibits an upturn behavior at low temperatures.The spin-lattice relaxation rate ^(1)T_(1)^(-1) is strongly enhanced when lowering the temperature,developing a broad peak at about 40 K,then decreases following a spin-wave-like behavior ^(1)T_(1)^(-1)∝T^(2) at lower temperatures.These results evidence a short-range glassy antiferromagnetic ordering of magnetic moments below 40 K and dominant antiferromagnetic fluctuations extending to much higher temperatures.Our findings reveal the strong electron correlations in bulk Nd_(0.85)Sr_(0.15)NiO_(2),and shed light on the mechanism of superconductivity observed in films of nickelates.

关 键 词：behavior FERROMAGNETIC SUPERCONDUCTIVITY 

分 类 号：O469[理学—凝聚态物理]