Search results for "Muon spin spectroscopy"

Spin transition in [Fe(phen)2(NCS)2] - �SR study

2004

The reversible thermal spin transition which occurs in [Fe(phen)(2)(NCS)(2)] around T-1/2 similar to 177 K has been investigated by muon spin relaxation (muSR) (similar to10-280 K). The depolarisation curves are well described by two Lorentzian lines represent fast and slow components in the decay curves, with the initial asymmetry parameter of the fast component found to track the spin transition in [Fe(phen)2(NCS),]. Comparison of zero-field and transverse field (20 Oe) muSR measurements shows that diamagnetic muonic species occur over the entire temperature range.

Spin Crossover in Fe(II) Molecular Compounds — Mössbauer and µSR Investigations

2002

The compound [Fe(ptz)6](C104)2 (ptz = 1-propyl-tetrazole) displays a complete and gradual spin crossover centred around 125 K as evidenced by magnetic and muon measurements over the temperature range ∼ 4.2–300 K. Although the crystal structure reveals only one crystallographic site, line broadening is observed in the Mossbauer spectra in the vicinity of the spin transition. The muon spin relaxation behaviour of this compound indicates that a structural transformation rather than dynamic processes may account for the observed spectral features. Both the Mossbauer and muon measurements are consistent with a mixture of high and low spin Fe ions in the transition region.

Quantum Phases and Spin Liquid Properties of 1T-TaS2

2021

Quantum materials exhibiting magnetic frustration are connected to diverse phenomena including high-Tc superconductivity, topological order and quantum spin liquids (QSLs). A QSL is a quantum phase (QP) related to a quantum-entangled fluid-like state of matter. Previous experiments on QSL candidate materials are usually interpreted in terms of a single QP, although theories indicate that many distinct QPs are closely competing in typical frustrated spin models. Here we report on combined temperature-dependent muon spin relaxation and specific heat measurements for the triangular-lattice QSL candidate material 1T-TaS2 that provide evidence for competing QPs. The measured properties are assig…

Slow magnetic fluctuations and superconductivity in fluorine-doped NdFeAsO

2015

Among the widely studied superconducting iron-pnictide compounds belonging to the Ln1111 family (with Ln a lanthanide), a systematic investigation of the crossover region between the superconducting and the antiferromagnetic phase for the Ln = Nd case has been missing. We fill this gap by focusing on the intermediate doping regime of NdFeAsO(1-x)F(x) by means of dc-magnetometry and muon-spin spectroscopy measurements. The long-range order we detect at low fluorine doping is replaced by short-range magnetic interactions at x = 0.08, where also superconductivity appears. In this case, longitudinal-field muon-spin spectroscopy experiments show clear evidence of slow magnetic fluctuations that …

Spin dynamics in the single-ion magnet [Er(W5O18)2]9−

2018

In this work we present a detailed NMR and ${\ensuremath{\mu}}^{+}\mathrm{SR}$ investigation of the spin dynamics in the new hydrated sodium salt containing the single-ion magnet ${[\mathrm{Er}{({\mathrm{W}}_{5}{\mathrm{O}}_{18})}_{2}]}^{9\ensuremath{-}}$. The $^{1}\mathrm{H}\phantom{\rule{0.16em}{0ex}}\mathrm{NMR}$ absorption spectra at various applied magnetic fields present a line broadening on decreasing temperature which indicates a progressive spin freezing of the single-molecule magnetic moments. The onset of quasistatic local magnetic fields, due to spin freezing, is observed also in the muon relaxation curves at low temperature. Both techniques yield a local field distribution of t…

Two hybrid organometallic-inorganic layered magnets from the series [ ZIIICp*2] [ MIIMIII(ox)3] studied with μ+SR

2004

We present zero-field muon spin relaxation (ZF-μ + SR) measurements on two examples of a new series of hybrid organometallic-inorganic layered magnets, namely ferromagnetic [FeCp* 2 ][MnCr(ox) 3 ] and ferrimagnetic [CoCp* 2 ][FeFe(ox) 3 ] (where ox = oxalate and Cp* = pentame- thyl-cyclopentadienyl). Both materials show multi-component muon spin precession signals characteristic of quasistatic magnetic fields at several distinct muon sites. The temperature dependence of the precession frequencies allow critical exponents to be extracted. Possible muon sites are discussed on the basis of dipole field calculations.

Muon spin rotation studies in single crystals of Zn and Cd

1981

Muon states in metals: Recent progress

1984

We report on our results in two interesting questions related to muon spin rotation studies in condensed matter: (i) energetics of muons in metals, including lattice relaxation and zero point motion in self-trapping phenomena, and (ii) systematics of Knight shifts and hyperfine fields.

Hysteresis in the spin transition regime of [Fe(NH2trz)3](NO3)2 as probed by ZF-μSR

2006

The thermal spin transition which occurs in the polymeric chain compound [Fe(NH(2)trz)(3)](NO3)(2) above room temperature has been investigated by zero-field muon spin relaxation (mu SR) (similar to 8-402 K). The depolarization curves are best described by a Lorentzian and a Gaussian line that represent fast and slow components respectively. The spin transition is associated with a hysteresis loop of width Delta T = 34 K (T-1/2(up arrow) = 346 K and T-1/2(down arrow) = 312 K) that has been delineated by the temperature variation of the initial asymmetry parameter. Comparison of zero-field and transverse field (20 Oe) mu SR measurements shows that diamagnetic muon species occur over the enti…

Importance of Spin-Orbit Interaction for the Electron Spin Relaxation in Organic Semiconductors

2013

Despite the great interest organic spintronics has recently attracted, there is only a partial understanding of the fundamental physics behind electron spin relaxation in organic semiconductors. Mechanisms based on hyperfine interaction have been demonstrated, but the role of the spin-orbit interaction remains elusive. Here, we report muon spin spectroscopy and time-resolved photoluminescence measurements on two series of molecular semiconductors in which the strength of the spin-orbit interaction has been systematically modified with a targeted chemical substitution of different atoms at a particular molecular site. We find that the spin-orbit interaction is a significant source of electro…