title: Magnetic properties and spin dynamics in Ba(Fe(1-x)Mn(x))2As2 compounds studied by 57Fe Mössbauer spectroscopy.
abstract: Ba(Fe(1-x)Mn(x))2As2 compounds with x = 0.016 and 0.064 have been studied by (57)Fe Mössbauer spectroscopy in the temperature range from 30 to 300 K. The unusual magnetic splitting spectra at lower temperatures have been analyzed using the distribution of hyperfine field. It is found that the influence of Mn dopant spreads beyond the nearest Fe magnetic moments, and the Fe 3d electrons behave more localized compared with those in the electron-doped compounds. This reduces the hyperfine interactions between iron nucleus and the sounding electrons. The shape of the spin density wave is near-rectangular at 6.4%-Mn doping, indicating quite different interband interactions compared with electron-doped compounds. A distinct broadening of the spectral linewidth around the spin density wave transition temperature has been observed and the spin correlation time is deduced according to the linewidth. The correlation time is further related to the spin-lattice relaxation rate by a simple model and the magnetic fluctuations can be explored effectively. It is found that the magnetic fluctuations of iron spins in Mn-doped compounds can be described well using a phenomenological two-component model and the resulting Curie-Weiss temperature is far from the quantum critical point at the present doping levels.
authors.affiliation: Institute of Applied Magnetics, Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, People's Republic of China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Ma
authors.forename: Jiangwei
authors.initials: J
authors.lastname: Bai
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Li
authors.forename: Jianmei
authors.initials: J
authors.lastname: Wan
authors.forename: Hua
authors.initials: H
authors.lastname: Pang
authors.forename: Fashen
authors.initials: F
authors.lastname: Li