A µSR study of magnetic ordering and metamagnetism in a bilayered molecular magnet

Abstract

Muon spin relaxation has been used to study the magnetic properties of a low-dimensional molecular magnet with a structure consisting of bilayers of [W(CN)8]3− and Cu2+. In the magnetically ordered state a spontaneous precession signal was found to contain two main components and the temperature dependence of the characteristic internal fields was followed up to the critical temperature. The critical exponent obtained for the magnetic order parameter β = 0.237(12) points to the two-dimensional character of the transition and reflects its underlying Berezinski–Kosterlitz–Thouless nature. Experiments performed in the longitudinal magnetic field demonstrate clearly a spin-flip phenomenon associated with the weak inter-bilayer coupling, that takes place in the magnetic field region below 100 G. The muon precession signals measured in the vicinity of this transition provide detailed local information about the corresponding rearrangements of the spin structure.

Hidden magnetic order in CuNCN

“…It is related to the static and dynamic local fields. 27 In contrast to the recent study by Zorko et al, 17 we clearly identify a nonzero internal field at 5 K in sample 1. Fig.…”

μSR investigation of magnetism and magnetoelectric coupling in Cu2OSeO3

“…The parameters σ 1 and σ 2 decrease with increasing temperature and drop to 0 at the Curie temperature T c = 57.0(1) K of the ferrimagnetic transition of Cu 2 OSeO 3 . The longitudinal relaxation rate λ is a measure of the internal magnetic-field dynamics and can be expressed by the fieldfield correlation function λ = γ 23 Here B ⊥ is the field component perpendicular to the muon-spin direction at the muon site. Brackets denote statistical averages.…”

Magnetic ordering in the double-layered molecular magnetCu(tetren)[W(CN)8Bałanda1, Pełka2, Wasiutyński3 et al. 2008Phys. Rev. B292180View full textAdd to dashboardCite

“…15 The subject of the study is the copper-tungsten cyanide coordination polymer ͕͑tetrenH 5 ͒ 0.8 Cu 4 II ͓W V ͑CN͒ 8 ͔ 4 · 7.2H 2 O͖ n ͑tetren = tetraethylenepentaamine͒ hereafter abbreviated as WCuT which was first reported by Podgajny et al 16 In Refs. [16][17][18][19] measurements carried out on powder samples by means of different techniques, i.e., ac and dc magnetometries, adiabatic calorimetry, and SR were reported. An anomalous behavior of ac susceptibility at the transition point T c = 33.4 K was noticed as well as the metamagnetic features below T c .…”

“…Based on the results above, the WCuT was understood as a set of ferromagnetic double layers interacting with neighboring bilayers with weak antiferromagnetic forces. The muon spin rotation and relaxation experiment performed by Pratt et al 19 still supplied more information on the magnetic ordering and nature of the field-induced metamagnetic transformation. A SR precession signal in the magnetically ordered state contained two components of the local magnetic field B 1 and B 2 .…”