Monday, February 12, 2018
Abstract-Macroscopic magnetization control by symmetry breaking of photoinduced spin reorientation with intense terahertz magnetic-nearfield
Takayuki Kurihara, Hiroshi Watanabe, Makoto Nakajima, Shutaro Karube, Kenichi Oto, YoshiChika Otani, and Tohru Suemoto
We exploit intense terahertz (THz) magnetic nearfield to nonthermally drive the symmetry breaking process of the ground state spin order during optically-induced spin reorientation phase transition in ErFeO3. More than 80 % of total magnetisation in the sample have been macroscopically aligned to selectable orientations by the time delay between THz and optical pulses, reflecting the phase of coherent magnon and the direction of exciting magnetic nearfields. The spin dynamics are well reproduced by equation of motion including time-dependent magnetic potential. By using nonresonant excitation, we revealed the symmetry breaking process caused directly by THz magnetic field without spin precession.