多鐵材料Cu2OCl2和Cu3BiO2(SeO3)2Cl的比熱

Abstract

我們分別對不同的多鐵性材料進行外加磁場平行c軸的比熱量測，為了瞭解比熱實驗在材料分析上的重要性。 從比熱結果可以很清楚的發現在Cu2OCl2上反鐵磁的臨界溫度在T = 70 K且在H = 5 T的磁場下此反鐵磁依然非常強壯。在Cu3Bi(SeO3)2O2Cl材料比熱結果中發現兩個相變，高溫T = 120 K的相變在不同磁場下比熱沒有改變，比較了磁性量測內也並沒有出現，說明此相變和磁性沒有關係。在低溫T = 27 K附近的相變會隨著磁場的加大而有改變，也因此發現了此材料的臨界磁場大約在H = 0.8 T，我們利用比熱結果和其他實驗的結果比較來了解此低溫的相變。 最後，在利用其他的實驗結果分別去和比熱結果比對的過程中，我們可以發現比熱量測在分析材料是一個非常有力的方法，可以明確的透析材料內的各種相變，並提供更多其他實驗沒有的發現。

In order to understand the importance of the specific heat experiment in material analysis, we have separately measured the specific heat with the magnetic field parallel to c-axis for different multiferroic materials. According to the results of specific heat, it is clear that the critical temperature of antiferromagnetism in Cu2OCl2 is still very strong at T = 70 K and at magnetic field of H = 5 T. The specific heat of Cu3Bi (SeO3) 2O2Cl material was found to have two phase transitions. The specific heat of the high temperature, T = 120 K, did not change in different magnetic fields. The magnetic measurements also did not show that the phase transition have any relationship with magnetic properties. The phase transition near the low temperature, T = 27 K, would change with the increase of the magnetic field. We also find that the critical magnetic field of this material is about H = 0.8 T, we used the results of specific heat and that of other experiments to realize the mechanism of low temperature phase transition. Finally, in comparison of the results of other experiments and the results of specific heat, we can find that the specific calorimetric analysis is a very powerful method for analyzing the various phase transitions, and it also can be used for dialysis in materials and provide more information which other experiments could not found.