This should be due to the anisotropy of the material, that is, its quasi-one-dimensional structure. Because there is a fixed crystal phase in the material, that direction has the strongest diamagnetism, so the magnetic field lines will always go along this direction, causing all The samples are all upright.
If the material is a one-dimensional superconductor where current can only flow with zero resistance along one direction, aligning that direction with the magnetic field lines should produce the weakest diagmanetism, because the magnetic force is proportional to the cross product of current and magnetic field. If the two are parallel, the force is zero.
Of course this could explain why the sample doesn't lift off: it starts out with the superconducting direction at an angle to the magnetic field and relatively strong diamagnetism leading to a righting force until the two directions are nearly aligned and the diamagnetism is too weak to overcome gravity.
这应该还是材料的各向异性, 也就是它的准一维结构导致. 因为材料当中有一个固定晶相, 那个方向的抗磁性最强, 所以磁感线总会沿着这个方向走, 导致所有样品都是竖起来的.
This should be due to the anisotropy of the material, that is, its quasi-one-dimensional structure. Because there is a fixed crystal phase in the material, that direction has the strongest diamagnetism, so the magnetic field lines will always go along this direction, causing all The samples are all upright.
https://www.zhihu.com/question/615044128/answer/3145337312