磁铁的磁性不是那么容易消除的，所以更有可能是磁铁在受到外场或其他机械和热刺激的突然刺激后，突然从磁化状态转变为外部结构。但是除了这种突然的变化，还有熵效应，我想，也许你背后的意思是想知道熵效应是否占主导地位。对于铁磁性材料，必须强调的是，在讨论铁磁性问题时，我们没有考虑到熵的部分，因为铁磁性还包含更长距离的相关性，彼此之间更强的自旋。函数，所以更有可能的是磁铁只是处于冻结状态，而不像液晶那样，最终通过取向主导整个相变。有许多不同类型的磁性材料，但由于它们表现出磁性，它们内部有某种取向的趋势。今天我们知道，这主要是由电子(有时是原子核)的轨道角动量、自旋角动量等引起的。材料被磁化后，发生了一些奇妙的变化。直觉上，它是磁性的。仔细看，材料是一种无序状态(所有方向都是一样的，这是各向同性的，这种情况可以想象成一个球)，现在有了一些方向性(有一些特殊的方向，这是各向异性，这种情况类似于棒子)，显然球的对称性比棒子的对称性更丰富，那么，磁化的过程就是对称性的降低，通常称为对称性破缺。一般来说，当使用这种磁化状态时，系统的能量会相对较低(甚至很低)，但这只是问题的一个方面。 Think about the expression of free energy: F=U-TS, we It is hoped that the free energy will decrease, although it is important to consider the energy reduction, but if the temperature is gradually increased, the increase of the system entropy can also reduce the free energy. The increase in entropy corresponds to an increase in the number of states in the microscopic state, that is, an increase in the number of states in the orientation can result in a decrease in free energy. In short, when the temperature is relatively high, the magnet can allow more kinds of orientations, which is one of the reasons that may cause the magnetic weakening. But this effect is very different for different magnetic materials. When the interaction strength between magnetic moments is strong enough (U dominates), the effect of entropy effect (TS) may actually be very weak. In fact, this is also the case. In general, this part of the effect of entropy may not be the main factor in the problem of the disappearance of magnet magnetism in what we usually call normal temperature.