在垂直和任意方向磁场中的六角形超导网络相边界

给出了在垂直外磁场和任意方向外磁场中的七节点六角形超导网络相边的精确解析表达式，由此表达式求出了两种情况下的六角形网络的相边界，得到了在任意方向外磁场中的网络相边界Ｔｃ（Ｈ）是以敏感和复杂的方式依赖于磁场大小和方向，并对相边界Ｔｃ（Ｈ）这些特性的某些应用给予了讨论。

The Phase Boumdary of Hexagon Superconduction Networks in a Perpendicular and an Arbitrary Direction External- Magnetic- Field

An exact analytic expression for the phase boundary T c(H) of a hexagon superconducting network made of 12 identical thin superconducting straight line segments in a perpendicular and an arbitrary direction external magnetic field is derived. The phase boundry of this network is shown to depend in a complex and sensitive way on both the magnitude and direction of the magnetic field in an arbitrary direction external magnetic field. The sensitive directional dependence is very interesting and should have some applicational vale. For example ,if the magnitude and the direction of an applied magnetic field are all preset at such values as to hold the T c of an hexagon superconducting network at one of the maxima,and the temperature T is kept constant at a value just below this T c(H) ,then any slight change of the orientation between the magnetic field and the hexagon network should lead to a large increase in the resistance of the networs which can be used clearly in a feedback circuit to control the orientation of a device or instrument. The Fig.5 (such as the vicinity of θ=60°) can help the readers understand this view. The sensitive directional dependence of the hexagon network is better than the square network's .