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arXiv · 1405.6806

Non-d$^0$ Electric Dipole in FeO$_5$ bipyramid: a New Resource for Quantum Paraelectrics, Ferroelectrics and Multiferroics

Shi-Peng Shen·Yi-Sheng Chai·Jun-Zhuang Cong·Pei-Jie Sun·Jun Lu·Li-Qin Yan·Shou-Guo Wang·Young Sun
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Abstract

Electric polarization in conventional ferroelectric oxides usually involves nonmagnetic transition-metal ions with an empty d shell (the d$^0$ rule). Here we unravel a new mechanism for local electric dipoles based on magnetic Fe$^{3+}$ (3d$^5$) ion violating the d$^0$ rule. The competition between the long-range Coulomb interaction and short-range Pauli repulsion in a FeO$_5$ bipyramid with proper lattice parameters would favor an off-center displacement of Fe$^{3+}$ that induces a local electric dipole. The manipulation of this kind of non-d$^0$ electric dipoles opens up a new route for generating unconventional dielectrics, ferroelectrics, and multiferroics. As a prototype example, we show that the non-d$^0$ electric dipoles in ferrimagnetic hexaferrites (Ba,Sr)Fe$_{12}$O$_{19}$ lead to a new family of magnetic quantum paraelectrics.

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Shi-Peng Shen, Yi-Sheng Chai, Jun-Zhuang Cong, Pei-Jie Sun, Jun Lu, Li-Qin Yan, Shou-Guo Wang, Young Sun. 2014-05-27. Non-d$^0$ Electric Dipole in FeO$_5$ bipyramid: a New Resource for Quantum Paraelectrics, Ferroelectrics and Multiferroics. https://doi.org/10.1103/physrevb.90.180404

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