Spin-Canting-Induced Improper Ferroelectricity and Spontaneous Magnetization Reversal in SmFeO3
Spin-Canting-Induced Improper Ferroelectricity and Spontaneous Magnetization Reversal in SmFeO3
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DOI：
10.1103/physrevlett.107.117201
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发表时间：
2011-09-06
影响因子：
8.6
通讯作者：
Scott, James F.
中科院分区：
文献类型：
--
作者：
Lee, Jung-Hoon;Jeong, Young Kyu;Scott, James F.
SmFeO 3是中心对称的稀土正铁氧体的一个家族，是已知的非铁电体。然而，我们已经发现，SmFeO 3是令人惊讶的铁电体在室温下沿着Pbnm的B轴具有小的极化。第一性原理计算表明，倾斜的反铁磁有序与两个不等价的自旋对是负责这种非凡的极化和反向Dzyaloshinskiii-Moriya相互作用占主导地位的交换伸缩机制的表现形式的不适当的铁电性。SmFeO 3还表现出一个有趣的现象，在低温下的自发磁化反转。这种反转归因于Sm自旋磁矩的激活，Sm自旋磁矩与Fe自旋磁矩反平行。
SmFeO3, a family of centrosymmetric rare-earth orthoferrites, is known to be nonferroelectric. However, we have found that SmFeO3 is surprisingly ferroelectric at room temperature with a small polarization along the b axis of Pbnm. First-principles calculations indicate that the canted antiferromagnetic ordering with two nonequivalent spin pairs is responsible for this extraordinary polarization and that the reverse Dzyaloshinskii-Moriya interaction dominates over the exchange-striction mechanism in the manifestation of the improper ferroelectricity. SmFeO3 further exhibits an interesting phenomenon of spontaneous magnetization reversal at cryogenic temperatures. This reversal is attributed to the activation of the Sm-spin moment which is antiparallel to the Fe-spin moment below similar to 5 K.