磁性物质中冷无序能的作用

在研究物质的磁性时,考虑了电子之间的正交换能(A1>0,导致电子自旋平行排列)和负交换能(A2<0,导致电子自旋反平行排列)两项各自的物理作用,不是简单地只以它们的代数和为判据.提出冷无序能的概念:当A1>|A2|(A=A1-|A2|>0)时,A1为有序能,A2为冷无序能;当A1<|A2|(A<0)时,A2为有序能,A1为冷无序能.物质的磁性决定于热运动能、有序能以及冷无序能之间的竞争.考虑了冷无序能导致“冷无序”的物理功能,将冷无序能变换为等效温度,在统计物理的框架内处理了铁磁性、反铁磁性转变和自旋玻璃冻结问题.A2=0的体系具有Weiss铁磁性,|A2|A1=1的体系表现自旋玻璃磁性,1>|A2|A1>0的体系同时具有铁磁性和自旋玻璃磁性,1>A1|A2|>0的体系同时具有反铁磁性和自旋玻璃磁性. 关键词： 交换能 冷无序能 铁磁性 反铁磁性 自旋玻璃

Cold-disorder energy in magnetic matter

The concept of cold-disorder energy which originates from the competition of terms with different signs in the exchange energy between electrons of magnetic matter has been introduced.The dominant term in the exchange energy of a magnetic system results in ordering of the system,whereas another term with different sign tends to disturb such an order.Thus the latter term could be defined as cold-disorder energy,which can be treated as an effective temperature.The magnetism of the system depends on the competition among the thermal motion,the order energy and the cold-disorder energy.The phase diagram is derived for the ferromagnetism,the antiferromagnetism,the spin glass and for the coexistence of these magnetic phases. When A 2=0 the system has Weiss ferromagnetism,when A 1=0 the system has Neel anti ferromagnetism,when A 1=|A 2| system has spin glass magnetism,and when A 1>|A 2| there is coexistence of ferromagnetism and spin glass in the the system,when A 1<|A 2| there is coexistence of antiferromagnetism and spin glass in the the system.