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Fogh, E.*; 木原 工*; Toft-Petersen, R.*; Bartkowiak, M.*; 鳴海 康雄*; Prokhnenko, O.*; 三宅 厚志*; 徳永 将史*; 及川 健一; Srensen, M. K.*; et al.
Physical Review B, 101(2), p.024403_1 - 024403_12, 2020/01
被引用回数:15 パーセンタイル:71.02(Materials Science, Multidisciplinary)Neutron diffraction with static and pulsed magnetic fields is used to directly probe the magnetic structures in LiNiPO up to 25 T and 42 T, respectively. By combining these results with magnetometry and electric polarization measurements under pulsed fields, the magnetic and magnetoelectric phases are investigated up to 56 T applied along the easy axis. In addition to the already known transitions at lower fields, three new ones are reported at 37.6, 39.4, and 54 T. Ordering vectors are identified with Q = (0, , 0) in the interval 37.6 - 39.4 T and Q = (0, 0, 0) in the interval 39.4 - 54 T. A quadratic magnetoelectric effect is discovered in the Q= (0, 0, 0) phase and the field dependence of the induced electric polarization is described using a simple mean-field model. The observed magnetic structure and magnetoelectric tensor elements point to a change in the lattice symmetry in this phase. We speculate on the possible physical mechanism responsible for the magnetoelectric effect in LiNiPO.
Sales, M.*; 篠原 武尚; Srensen, M. K.*; Knudsen, E. B.*; Tremsin, A.*; Strobl, M.*; Schmidt, S.*
Journal of Physics D; Applied Physics, 52(20), p.205001_1 - 205001_6, 2019/05
被引用回数:7 パーセンタイル:37.59(Physics, Applied)Three dimensional polarimetric neutron tomography is an emerging method for nondestructive investigation of magnetic field strength and direction distribution in three dimensions. It utilises the Larmor precession of the neutron spin in the presence of an external magnetic field and has so far been restricted to the measurement of magnetic fields weak enough to keep the neutron precession below the phase-wrapping limit at 180 degree. Through the use of polychromatic time-of-flight information in combination with an iterative forward model reconstruction algorithm we have gone beyond this limit, thereby vastly broadening the potential of the technique. We present the reconstructed magnetic field of a measured current carrying solenoid as a proof-of-principle for this novel method, as well as successfully applying the method to a simulated data set of a sample consisting of multiple magnetic domains.