顺电体材料的磁学及磁电性质研究

The investigated the giant magnetocaloric effect of perovskite quantum paraelectric materials have been a very important research topic due to the possibility of its broad application at room temperature magnetic refrigeration and magnetic device fabrication. In this item, the magnetic properties and magnetoelectric coupling effect of the quantum paraelectric materials will be studied. The following two aspects will be important discussed. (1) The magnetic Eu ion spin exchange constants of paraelectric materials will be accurately obtained. So we can determine the magnetic lattice structure paraelectric material from the theory. Meanwhile, the effect quantum spin fluctuation on the magnetic properties and magnetoelectric properties of quantum paraelectric materials will be studied. (2) The relation between magnetoelectric coupling and dielectric constant, as well as their internal mechanism, will be investigated. And the mathematical expressions for relation between the dielectric constant and the pair correlation of neighboring spin will be given for compounds. The research item can not only help us to enhance the magnetoelectric coupling effect, but also for understanding the mechanism of paraelectric materials of magnetoelectric coupling effect has important academic significance.

具有钙钛矿型的顺电材料由于其表现出的巨磁容效应，在室温致冷和磁性器件制备方面具有广阔的应用前景而成为一个重要的研究课题。在本项目中，我们将对量子顺电体材料的磁学及磁电性质进行研究，重点讨论如下两个方面的内容：（1）精准确定顺电材料磁性粒子自旋间的交换常数，从理论上确定顺电材料的磁性晶格结构，同时研究量子自旋扰动对顺电体化合物的磁性质及磁电效应的影响。（2）探讨磁电藕合与介电常数之间的关系及内在机理，提出一个自旋关联函数与介电常数之间更为合理的数学表达式。该项目的研究不仅有助于提高顺电材料的磁电效应，而且对于理解顺电材料的磁电效应的形成机理有着重要的学术意义。

具有钙钛矿型的顺电材料由于其表现出的巨磁容效应，在室温致冷和磁性器件制备方面具有广阔的应用前景而成为一个重要的研究课题。我们主要以两种顺电材料EuTiO3和EuZrO3为例，详细的探讨了其磁性质。我们采用格林函数方法，研究了其磁性离子间的交换参数，通过解析的手段，得到了一种确定磁性材料中磁性离子间交换参数的有效方法。通过进一步的研究表明，该技巧可以被应用探讨磁性材料的磁结构类型。同时，为了探究量子扰动对系统磁性质的影响。我们采用了包括磁场、掺杂和磁晶各向异性等方法，从多个方面来改变各种不同的微观机制，从而达到有效探究量子扰动对系统磁性质的影响。目前的研究丰富多铁研究的基础理论，同时对于理解顺电材料的磁电效应的形成机理有着重要的学术意义。