title: Spin dynamics of the S = 5/2 2D triangular antiferromagnet Ba3NbFe3Si2O14.
abstract: We report pulse-field magnetization, ac susceptibility, and 100 GHz electron spin resonance (ESR) measurements on the S = 5/2 two-dimensional triangular compound Ba3NbFe3Si2O14 with the Néel temperature T(N) = 26 K. The magnetization curve shows an almost linear increase up to 60 T with no indication of a one-third magnetization plateau. An unusually large frequency dependence of the ac susceptibility in the temperature range of T = 20-100 K reveals a spin-glass behavior or superparamagnetism, signaling the presence of frustration-related slow magnetic fluctuations. The temperature dependence of the ESR linewidth exhibits two distinct critical regimes; (i) ΔH(pp)(T) is proportional to (T-T(N))(-p) with the exponent p = 0.2(1)-0.2(3) for temperatures above 27 K, and (ii) ΔH(pp)(T) is proportional to (T-T*)(-p) with T* = 12 K and p = 0.8(1)-0.8(4) for temperatures between 12 and 27 K. This is interpreted as indicating a dimensional crossover of magnetic interactions and the persistence of short-range correlations with a helically ordered state.
authors.affiliation: Department of Physics, Chung-Ang University, Seoul, Republic of Korea. kchoi@cau.ac.kr
authors.forename: K Y
authors.initials: KY
authors.lastname: Choi
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: A
authors.initials: A
authors.lastname: Ozarowski
authors.forename: J
authors.initials: J
authors.lastname: van Tol
authors.forename: H D
authors.initials: HD
authors.lastname: Zhou
authors.forename: C R
authors.initials: CR
authors.lastname: Wiebe
authors.forename: Y
authors.initials: Y
authors.lastname: Skourski
authors.forename: N S
authors.initials: NS
authors.lastname: Dalal
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D060328:Magnetic Phenomena; D017640:Silicates / Q000737:chemistry*; D013696:Temperature
chemical_list: C470742:La3Ga5SiO14; D017640:Silicates