【摘要】 我们在制备的EuBa₂Cu₃O_7-x多晶块样品上,用标准四引线法测量了其升场和降场时的I_c—H关系。发现临界电流对外磁场循环是不可逆的,这种不可逆性来自样品的颗粒性。我们还进一步观察到依所施加的最大外磁场H_max不同,不可逆性可分为两类,可用不同磁通俘获机制加以解释。更多还原

【Abstract】 A study about critical current dependence of polycrystalline bulk EuBa2-Cu3O7-x on an applied magnetic field has been made. It is shown that Ic versus B can be related to the granular characteristics of the sample , that is the fraunhofer diffraction structure of weak links between the grains and induced screening current .It is further observed that Ic(B)shows an irreversibility with cycle in an applied field when the sample is at LN2 temperature and the irreversibility can be divided into two type for different maxima applied field. This result can be interpreted in terms of flux trapped in the loops containing weak links and flux pinned in the EuBa2Cu3O7_x grains.更多还原