Polar phonon mixing in magnetoelectric EuTiO3

被引：68

作者：

Goian, V. ^{[1
]}

Kamba, S. ^{[1
]}

Hlinka, J. ^{[1
]}

Vanek, P. ^{[1
]}

Belik, A. A. ^{[2
]}

Kolodiazhnyi, T. ^{[3
]}

Petzelt, J. ^{[1
]}

机构：

[1] ASCR, Inst Phys, Prague 18221 8, Czech Republic

[2] Natl Inst Mat Sci, Int Ctr Mat Nanoarchitecton, Tsukuba, Ibaraki 3050044, Japan

[3] Natl Inst Mat Sci, OMC, Tsukuba, Ibaraki 3050044, Japan

来源：

EUROPEAN PHYSICAL JOURNAL B | 2009年 / 71卷 / 03期

关键词：

78.30.-j Infrared and Raman spectra; 77.22.-d Dielectric properties of solids and liquids; 75.80.+q Magnetomechanical and magnetoelectric effects, magnetostriction;

D O I：

10.1140/epjb/e2009-00205-5

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

Infrared reflectivity spectra of antiferromagnetic incipient ferroelectric EuTiO3 were investigated up to 600 K. Three polar phonons typical for the cubic perovskite Pm (3) over barm structure were observed. Analysis of phonon plasma frequencies showed that the lowest-energy TO1 phonon corresponds predominantly to the Slater mode describing vibration of Ti cations against the oxygen octahedra and the TO2 phonon expresses vibrations of the Eu cation against the TiO6 octahedra. The highest frequency TO4 phonon represents O-octahedra bending. Incipient ferroelectric behavior of the permittivity is caused by pronounced softening of the TO1 phonon, which is coupled to the TO2 mode. Although the Eu cations are not involved in the TO1 mode, the spin ordering of the 4f electrons at Eu cations has influence on the frequency of the TO1 mode due to Eu-O-Eu super-exchange interaction. This is probably responsible for the 7% change of the permittivity induced by the magnetic field in the antiferromagnetic phase, as reported by Katsufuji and Takagi [Phys. Rev. B 64, 054415 ( 2001)].

引用

页码：429 / 433

页数：5

共 20 条

[1] DIELECTRIC CONSTANT IN PEROVSKITE TYPE CRYSTALS [J].