Spin–lattice relaxation

Summary

During nuclear magnetic resonance observations, spin–lattice relaxation is the mechanism by which the longitudinal component of the total nuclear magnetic moment vector (parallel to the constant magnetic field) exponentially relaxes from a higher energy, non-equilibrium state to thermodynamic equilibrium with its surroundings (the "lattice"). It is characterized by the spin–lattice relaxation time, a time constant known as T1. There is a different parameter, T2, the spin-spin relaxation time, which concerns the exponential relaxation of the transverse component of the nuclear magnetization vector ( to the external magnetic field). Measuring the variation of T1 and T2 in different materials is the basis for some magnetic resonance imaging techniques. Nuclear physics T1 characterizes the rate at which the longitudinal Mz component of the magnetization vector recovers exponentially towards its thermodynamic equilibrium, according to equation M_z(t) = M_{z,

Official source

https://en.wikipedia.org/wiki/Spin%E2%80%93lattice_relaxation

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (22)

Related publications

Related people (3)

Related people

Related units (2)

Related units

Related concepts (8)

Related concepts

Related courses (4)

Related courses

Related lectures (9)

Related lectures

Exploring the role of white matter connectivity in cortex maturation

Alessandra Griffa, Patric Hagmann, Petra Susan Hüppi

The maturation of the cortical gray matter (GM) and white matter (WM) are described as sequential processes following multiple, but distinct rules. However, neither the mechanisms driving brain maturation processes, nor the relationship between GM and WM maturation are well understood. Here we use connectomics and two MRI measures reflecting maturation related changes in cerebral microstructure, namely the Apparent Diffusion Coefficient (ADC) and the T1 relaxation time (T1), to study brain development. We report that the advancement of GM and WM maturation are inter-related and depend on the underlying brain connectivity architecture. Particularly, GM regions and their incident WM connections show corresponding maturation levels, which is also observed for GM regions connected through a WM tract. Based on these observations, we propose a simple computational model supporting a key role for the connectome in propagating maturation signals sequentially from external stimuli, through primary sensory structures to higher order functional cortices.

2017

The quantum antiferromagnet Cu2Te2O5Br2 was investigated by NMR and nuclear quadrupole resonance (NQR). The Te-125 NMR investigation showed that there is a magnetic transition around 10.5 K at 9 T, in agreement with previous studies. From the divergence of the spin-lattice relaxation rate, we ruled out the possibility that the transition could be governed by a one-dimensional divergence of the spin-spin correlation function. The observed anisotropy of the Te-125 shift was shown to be due to a spin polarization of the 5s(2) "E" doublet of the [TeO3E] tetrahedra, highlighting the importance of tellurium in the exchange paths. In the paramagnetic state, Br NQR and NMR measurements led to the determination of the Br hyperfine coupling and the electric field gradient tensor, and to the spin polarization of Br p orbitals. The results demonstrate the crucial role of bromine in the interaction paths between Cu spins.

2010

We performed an Eu153 and Eu151 NMR study of EuO and Gd doped EuO using a home-made spectrometer designed to measure signals with fast spin-spin relaxation times. We determined and described the broadening mechanisms giving rise to the structure in the lineshape of pure EuO. The complete description of the lineshape of pure EuO allowed us to highlight the influence of doping EuO with Gd impurities on the lineshape. We demonstrated the presence of a temperature dependent static magnetic inhomogeneity in Gd doped EuO by studying the temperature dependence of the lineshapes. Our results suggested that the inhomogeneity in 0.6% Gd doped EuO was linked to colossal magnetoresistance. We also determined and described the origin and the temperature dependence of both the spin-spin and the spin-lattice relaxation mechanisms. The measurement of the spin-lattice relaxation times as a function of temperature led to the determination of the value of the exchange integral as a function of Gd doping.

EPFL2003