Magnetic-field-induced ferroelectric states in centrosymmetric R2BaCuO5 (R = Dy and Ho)

Article

关键词: OXIDES;    METAMAGNETISM;    POLARIZATION;    TRANSITIONS;    HO2BACUO5;    DY2BACUO5;    TM;    EU;    YB;   

DOI  :  10.1103/PhysRevB.104.144401

来源: SCIE

【 摘 要 】

The linear magnetoelectric effect and multiferroicity phenomena occur independently due to breaking inversion symmetry below the magnetically ordered state of either transition metal or rare-earth ions. Here, we report the occurrence of a linear magnetoelectric effect and magnetic field-induced ferromagnetism and ferroelectricity below T-N(R) in the orthorhombic green phases R2BaCuO5 (R = Dy and Ho). They undergo a long-range antiferromagnetic ordering of Cu-2(+) (T-N(Cu) = 18.5 and 17.5 K) and R3+ ions (T-N(DY) = 10.7 K and T-N(Ho) = 8 K). The neutron diffraction study reveals that these compounds undergo a first-order magnetic transition from the high-temperature centrosymmetric antiferromagnetic phase (P(b)112(1)/n) to the low-temperature noncentrosymmetric phases Pnm'a (Dy) and P112'(1)/a (Ho), which allow linear magnetoelectric coupling. This is consistent with field-induced electric polarization, below T-N(R) which varies linearly up to similar to 1.2 T. Above a critical field (H-c > 1.2 T), both compounds exhibit metamagnetic transitions with magnetization close to the saturation value M-s similar to 10.1 mu(B)/f.u. (Dy) and similar to 11.8 mu(B) /f.u. (Ho) at 7 T. Above the metamagnetic transition, a new polar state appears with large electric polarization, indicating field-induced ferroelectricity. We discuss the important role of 4f-3d coupling in determining the ground state magnetic structure responsible for the magnetoelectric coupling in both compounds.

【 授权许可】

Free