高压下L1_0-FePd晶态合金的物性研究

Study of the Properties in the L1_0-FePd Crystalline Alloy at High Pressure

采用基于密度泛函理论(DFT)的第一性原理平面波的方法,结合广义梯度(GGA)近似计算了高压下四方相L1_0-FePd晶态合金的结构稳定性、晶格常数、焓差、磁性及电子态密度.计算得出压力小于170 GPa时,考虑磁性的体系比不考虑磁性的体系更稳定,呈铁磁态合金,L1_0-FePd晶态合金的磁矩随着压力的增大不断减小;当压力大于170 GPa时,考虑磁性的体系与不考虑磁性的体系的焓基本相同,且体系的铁磁性消失,电子极化态密度趋于对称.因此,L1_0-FePd铁磁性合金的铁磁性坍塌临界压力处于170 GPa附近.

The structural stability,lattice constants, enthalpy difference, magnetic properties and electron- ical density of states of the L10-FePd crystalline alloy at high pressure were investigated by using first- principles calculation based on the density functional theory （DFT） within the framework of generalized gradient approximation （GGA）. The results of calculation show that the system of considering the mag- netic is more stable than without considering magnetic at the pressure below 170 GPa. The L10-FePd crys- tal alloy is ferromagnetic and the magnetic moment decrease with the pressure increase. When the pressure is above 170 GPa, the enthalpy of the system considering the magnetic is same with the without system the ferromagnetism disappear, and the electronic polarizationdensity of states becomes symmetrical. As the facts the ferromagnetic collapse critical pressure of tetragonal phase L1 o-FePd ferromagnetism alloy is near 170 GPa.