[1] Eerenstein W,Mathur N D,Scott J F. Multiferroic and magnetoelectric materials[J]. Nature,2006,442: 759-765.
[2] Ramesh R,Spaldin N A. Multiferroics: progress and prospects in thin films[J]. Nat Mater,2007,6: 21-29.
[3] Hur N,Park S,Sharma P A,et al. Electric polarization reversal and memory in a multiferroic material induced by magnetic fields[J]. Nature,2004,429: 392-395.
[4] Kimura T,Goto T,Shintani H,et al. Magnetic control of ferroelectric polarization[J]. Nature,2003,426: 55-58.
[5] Goto T,Kimura T,Lawes G,et al. Ferroelectricity and giant magnetocapacitance in perovskite rare-earth manganites[J]. Phys Rev Lett,2004,92: 257 201( 1 - 4) .
[6] Tachibana M,Shimoyama T,Kawaji H,et al. Jahn-Teller distortion and magnetic transitions in perovskite RMnO3 ( R = Ho, Er,Tm,Yb,and Lu) [J]. Phys Rev B,2007,75: 144 425( 1 - 5) .
[7] Lorenz B,Wang Y Q,Chu C W. Ferroelectricity in perovskite HoMnO3 and YMnO3 [J]. Phys Rev B,2007,76: 104 405 ( 1 - 3) .
[8] Lin T H,Hsieh C C,Shih H C,et al. Anomalous magnetic ordering in b-axis-oriented orthorhombic HoMnO3 thin films[J]. Appl Phys Lett,2008,92: 132 503( 1 - 3) .
[9] Hotta T,Moraghebi M,Feiguin A,et al. Unveiling new magnetic phases of undoped and doped manganites[J]. Phys Rev Lett,2003,90: 247 203( 1 - 4) .[10] Salafranca J,Brey L. Phase diagram and incommensurate phases in undoped manganites[J]. Phys Rev B,2006,73: 024 422( 1 - 9) .
[11] Sergienko I A,Sen C,Dagotto E. Ferroelectricity in the magnetic E-phase of orthorhombic perovskites[J]. Phys Rev Lett, 2006,97: 227 204( 1 - 4) .[12] Picozzi S,Yamauchi K,Sanyal B,et al. Dual nature of improper ferroelectricity in a magnetoelectric multiferroic[J]. Phys Rev Lett,2007,99: 227 201( 1 - 4) .
[13] Kimura T,Lawes G,Goto T,et al. Magnetoelectric phase diagrams of orthorhombic RMnO3 ( R = Gd,Tb,and Dy) [J]. Phys Rev B,2005,71: 224 425( 1 - 13) .
[14] Goto T,Yamasaki Y,Watanabe H,et al. Anticorrelation between ferromagnetism and ferroelectricity in perovskite manganites [J]. Phys Rev B,2005,72: 220 403( R) ( 1 - 4) .
[15] Zhang G Q,Luo S J,Dong S,et al. Enhanced ferroelectricity in orthorhombic manganites Gd1 - xHoxMnO3 [J]. J Appl Phys,2011,109: 07D901( 1 - 3) .[16] Perdew J P,Burke K,Ernzerhof M. Generalized gradient approximation made simple[J]. Phys Rev Lett,1996,77: 3 865-3 868.
[17] Kresse G,Furthmuller J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set[J]. Phys Rev B,1996,54: 11 169-11 186.
[18] Mori T,Kamegashira N,Aoki K,et al. Crystal growth and crystal structures of the LnMnO3 perovskites: Ln = Nd,Sm,Eu and Gd[J]. Mater Lett,2002,54: 238-243.
[19] Yamauchi K,Freimuth F,Stefan Blügel,et al. Magnetically induced ferroelectricity in orthorhombic manganites: microscopic origin and chemical trends[J]. Phys Rev B,2008,78: 014 403( 1 - 10) .
[20] Hemberger J,Schrettle F,Pimenov A,et al. Multiferroic phases of Eu1 - xYxMnO3 [J]. Phys Rev B,2007,75: 035 118( 1 - 8) .