First-principles methods are employed to understand the existence of magnetic-domain-wall-induced electric polarization observed in rare-earth iron garnets. In contrast with previous beliefs, it is found that the occurrence of such polarization neither requires the local magnetic moments of the rare-earth ions nor non-collinear magnetism. It can rather be understood as originating from a magnetoelectric effect arising from ferromagnetic interactions between octahedral and tetrahedral Fe ions at the domain walls, and the mechanism behind is found to be a symmetric exchange-striction mechanism.

中文翻译：

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稀土铁石榴石系统中磁畴壁诱导的电极化：第一性原理研究

第一原理方法被用来理解在稀土铁石榴石中观察到的磁畴壁感应的极化的存在。与以前的观点相反，发现这种极化的发生既不需要稀土离子的局部磁矩也不需要非共线磁性。可以将其理解为源自在畴壁处的八面体和四面体Fe离子之间的铁磁相互作用引起的磁电效应，并且发现其背后的机理是对称的交换限制机理。