钬铝石榴石晶场参数调整

Adjustment in crystal field parameters of Ho_3Al_5O_(12)

利用比热实验值,对钬铝石榴石(Ho_3Al_5O_(12))晶体的晶场参数进行了调整,依此计算了Ho_3Al_5O_(12)晶体的晶场能谱、Zeeman劈裂能级和波函数.在外磁场H=0时,分别计算了Ho_3Al_5O_(12)晶体的总比热、总熵随温度的变化,以及外磁场H=10kOe时该晶体倒数磁化率的温度关系,理论计算结果均与已有实验数据符合较好.该工作为进一步探究该晶体的其它性质奠定了必要的理论基础,对实际生产和科学研究中磁制冷材料的优化选取也具有一定的现实意义.

A set of crystal field （CF） parameters of Ho3Al5O12 （HoAG） crystals is adjusted by using the measured data of specific heat in this study. By means of the adjusted CF parameters, the CF- and external magnetic field- split ground state of Ho3＋ in HoAG has been calculated based on the quantum theory. The calculated results show that the CF ground state of Ho3＋ is singlet in HoAG. The calculated results of total specific heat are obtained by using the adjusted and the published elsewhere CF parameters respectively. It is found that the calculated results by using the adjusted CF parameters are in better agreement with the experimental data. The results indicate that the adjusted CF parameters presented in this paper are reliable indeed. On the basis of the results, the thermal variation of the reciprocal magnetic susceptibility and the total entropy of HoAG are obtained theoretically in the applied magnetic field H = 10kOe and H = 0 respectively. The calculated results are in good agreement with the measured data. These results prove that the adjusted CF parameters in this paper are reliable again. This research lays an important theoretical basis on the magnetic properties of the crystal further study. It is also helpful to select suitable magnetic refrigeration materials for the scientific research and practical production.