NMR Studies of the magnetic order in the Oxide High-Tc Superconductor

在4.2~300K温度范围内，测量了掺氢四方YBa2Cu3O&lt；6+x&gt；Hy四种不同氧、氢原子浓度类型(x，y)的样品(x，y)，(0.07，0.118)，(0.1，0.14)，(0.11，0.078)和(0.17，0.01)的反铁磁相的铜(1)核磁共振，零场核磁共振和质子核磁共振。~1H核磁共振谱线宽在20K以下突然增大，T_2^&lt；-1&gt；和T_1^&lt；-1&gt；分别在20K和40K附近增强。^&lt；63&gt；Cu(1)NQR的T_1驰豫机制在T_m=80K左右发生变化，其磁化恢复随时间的变化表现为T&lt；T_m的非指数型和T&gt；T_m的指数型，T_m以下T_1的主要起因是空穴掺杂效应引起的Cu(1)或Cu(2)位上的Cu^&lt；2+&gt；磁矩的起伏。在T_m以上，T_1^&lt；-1&gt；Cu(1)NQR随温度的升高而逐渐增大，但在150K以上几乎不受温度的影响，这不能用Cu(2)O_2面上有序的AFCu^&lt；2+&gt；矩的影响和晶格振动的拉曼过程来解释。

Cu (1) NQR,Cu (2) zero field NMR,and Proton NMR have been measured in the antiferromagnetic phase of powdered samples of hydrogen-doped tetragonal YBa_2Cu_3O_<6+x>H_y from 4.2 to 300 K.Four samples with different concentration types of oxygen and hydrogen atoms (x, y), which are (0.07,0.118), , (0.1,0.14), (0.11,0.078), and (0.17,0.01), were used. The line width of ^1H NMR increases abruptly below 20 K.The enhancements of T_2^<-1> and T_1^<-1> of ^<63>Cu (1) NQR occur around 20 and 40 K,respectively. The relaxation mechanism of T_1 of ^<63>Cu (1) NQR changes at T_m=about 80 K and the time dependence of its magnetization recovery shows a nonexponential type for T < T_m and an exponential one for T > T_m. The predominant origin for T_1 below T_m is found to be the fluctuating magnetic fields due to the staggered Cu^<2+> moments on the Cu (1) or Cu (2) site induced by the hole doping effect. Above T_m, T_1^<-1> of ^<63>Cu (1) NQR increases gradually with temperature but it is almost temperature independent above 150 K,what can not be explained by the effect of the ordered AF Cu^<2+> moments in the Cu (2) O_2 plane and also by the Raman process of the lattice vibrations.