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arXiv · 0912.2584

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

T. Nakajima·S. Mitsuda·S. Kanetsuki·M. Yamano·S. Iwamoto·Y. Yoshida·H. Mitamura·Y. Sawai·M. Tokunaga·K. Kindo·K. Prokes·A. Podlesnyak
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Abstract

We have investigated magnetic field dependences of a ferroelectric incommensurate-helimagnetic order in a trigonal magneto-electric (ME) 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 CuFe1-xAxO2 systems (A=Al, Ga).

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T. Nakajima, S. Mitsuda, S. Kanetsuki, M. Yamano, S. Iwamoto, Y. Yoshida, H. Mitamura, Y. Sawai, M. Tokunaga, K. Kindo, K. Prokes, A. Podlesnyak. 2009-12-14. Anisotropic magnetic field responses of ferroelectric polarization in a trigonal multiferroic CuFe1-xAlxO2 (x=0.015). https://doi.org/10.1103/physrevb.81.014422

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