[15a-D221-1~7] 9.5 New functional materials and new phenomena

[15a-D221-4] The spin fluctuation on the magnetic-dielectric state in BiFeO₃

〇Hirotaka Okabe^1,3, Masatoshi Hiraishi^2,3, Shoichiro Nishimura^3,4, Jumpei Nakamura³, Takashi Honda^3,4, Ryosuke Kadono^3,4, Koichiro Shimomura^3,4, Masaki Fujita¹, Akihiro Koda^3,4 (1.Tohoku Univ., 2.Ibaraki Univ., 3.KEK-IMSS, 4.SOKENDAI)

Keywords:multiferroic, spin fluctuations, muon

I will discuss critical phenomena in cross-correlated electric and magnetic materials from the viewpoint of microscopic dynamical properties. Local spin fluctuations near the phase transition point of BiFeO₃, a type of cross-correlated material with different phase transition points, were measured by the muon spin rotation relaxation (μSR) method. By analyzing the longitudinal relaxation rate of muons, it was found that the electron spins of iron belong to the Ising-like universality class in the paramagnetic-ferroelectric state just above the Néel temperature.