【摘要】 分别测量了GdBa2Cu3O7-δ薄膜样品在H//c和H//ab时多个磁场下以及H=4T时不同角度下的的R-T曲线。低电阻区的电阻温度关系可以用磁通玻璃模型来解释,从中得到不可逆磁场-温度关系与R-T曲线上R/Rn=0.05%定义的磁场-温度关系相一致。H//c和H//ab两种情形下得到的磁场-温度关系具有较大差别表明不同的晶轴方向存在着不同的磁通钉扎行为。基于三维Ginzburg-Landau理论的有效磁场标度方程得到恒定磁场下不可逆温度随角度的变化关系获得了各向异性参数γ=7.3,表明GdBa2Cu3O7-δ薄膜的各向异性较大。更多还原

【Abstract】 R-T curves is measured in the GdBa2Cu3O7-δ thin film in several fixed values of magnetic field with H//c and H// ab respectively and in rotated field with several fixed orientations when H=4 T. The temperature dependence of the resistance in the low resistance region can be explained by the Vortex Glass (VG) model. And the obtained relation between the irreversibility field and temperature in VG model is in good fit with the data obtained from the R-T curves defined by R/Rn=0.05%. The large difference of the relation of field and temperature between the case of H//c and H//ab indicates that different vortex pinning behavior exists for different crystallographic axis. We have obtained the fitting equation for the angular dependence of the irreversibility temperature by the scaling function for the effective magnetic field based on the 3D Ginzburg-Landau theory and obtained the anisotropy parameter γ=7.3. This indicates a rather high anisotropy in the GdBa2Cu3O7-δ thin film.更多还原