Anisotropic magnetic field responses of ferroelectric polarization in the trigonal multiferroic CuFe1-xAlxO2 (x=0.015)

作者：Nakajima Taro^*; Mitsuda Setsuo; Kanetsuki Shunsuke; Yamano Motoyoshi; Iwamoto Shunsuke; Yoshida Yukihiko; Mitamura Hiroyuki; Sawai Yoshiki; Tokunaga Masashi; Kindo Koichi; Prokes Karel; Podlesnyak Andrey

来源：Physical Review B, 2010, 81(1): 014422.

DOI：10.1103/PhysRevB.81.014422

We have investigated magnetic field dependences of a ferroelectric incommensurate-helimagnetic order in a trigonal magnetoelectric multiferroic CuFe1-xAlxO2 with x=0.015, which exhibits the ferroelectric phase as a ground state, by means of neutron diffraction, magnetization, and dielectric polarization measurements under magnetic fields applied along various directions. From the present results, we have established the H-T magnetic phase diagrams for the three principal directions of magnetic fields; (i) parallel to the c axis, (ii) parallel to the helical axis, and (iii) perpendicular to the c and the helical axes. While the previous dielectric polarization (P) measurements on CuFe1-xGaxO2 with x=0.035 have demonstrated that the magnetic field dependence of the "magnetic domain structure" results in distinct magnetic field responses of P [S. Seki et al., Phys. Rev. Lett. 103, 237601 (2009)], the present study have revealed that the anisotropic magnetic field dependence of the ferroelectric helimagnetic order "in each magnetic domain" can be also a source of a variety of magnetic field responses of P in CuFe(1-x)A(x)O(2) systems (A=Al, Ga).

• 出版日期2010-1