Ti-50.8%Ni合金的类金属电磁特性

研究TiNi合金的宏观电磁性质与微观电子态的关系. 由TiNi合金样品的霍尔效应实验得出样品的霍尔系数为9.6×10-6 Ωm·T~(0.1). 由霍尔系数求得电子浓度n为6.5×10~(23)/m~3, 比金属电子浓度n的值小5个量级, 电学性质比金属弱得多. 而磁性测量得出TiNi合金中有很少的铁磁性晶粒, 但铁磁相很弱, 顺磁相为主相. 样品的表观顺磁磁化率为χ=(2.55±0.01)×10~(-4)(SI), 实际的顺磁磁化率的数值为4.3×10~(-4)(SI), 比金属的Pauli顺磁磁化率的数值大一个量级. TiNi合金与金属相比, 电性弱而磁性强. 电磁实验结果证明TiNi合金未满的3d与4s电子杂化后成为巡游电子, 与金属的公有化电子相比, 它们的载流能力减弱, 而局域磁性增强.

Semimetal Electromagnetic Characteristics of Ti-50.8%Ni Alloy

The relationship between the macroscopic electromagnetic property and microscopic electron state was studied. The Hall coefficient of the TiNi alloy sample obtained by Hall effect experiment was 9.6×10~(-6) Ωm·T~(-1). The electron density was 6.5×10~(23)/m~3 according to the Hall coefficient, it was 5 orders of magnitude less than the electron density of typical metals, and had much weaker electrical property than that of metals. The magnetism measurement showed that there were few ferromagnetic crystal grains in TiNi alloy. Since the ferromagnetic crystal grains were only a small portion of the sample, the ferromagnetic phase was weak and the paramagnetic phase was the main phase. The apparent paramagnetic susceptibility χ of the sample was (2.55±0.01)×10~(-4)(SI) and the actual value of the paramagnetic susceptibility was 4.3×10~(-4)(SI), both of them were one order greater than that of the Pauli paramagnetic susceptibilities of typical metals. Compared with metals, the electricity of TiNi alloy was weaker and the magnetism was stronger. The experiments mentioned above proved that the unfilled 3d and 4s electrons of the TiNi alloy became itinerant electrons after being hybridized. Compared with free electron of metals, the current carrying capacity was lowered, while the local magnetism was enhanced.