Magnetic polarization

Low resolution spectrometers utilize a low-field permanent magnet to generate the polarizing magnetic field. The range of magnetic field strengths is from 0.01 to... 

Let s consider an SMM, which is magnetized to a magnetization, M0, with a polarizing magnetic field, H. After (fast) removal of the field, the magnetization will decay exponentially with a single characteristic relaxation time (t) ... 

Fig. 5. Transverse relaxation times of carbonyl carbon as a function of rotational correlation time, rc (a), at four polarizing magnetic field strengths, and as a function of field strength, B0, against four different correlation times (b), according to Eq. (1).

Figure 3. Cross polarization magnetization for the PIP-cured epoxy under the SL (Hartmann-Hahn) condition. The cross polarization contact time is rcp. The decay corresponds to proton T,p relaxation.

At high temperatures, ferroelectric materials transform to the paraelectric state (where dipoles are randomly oriented), ferromagnetic materials to the paramagnetic state, and ferroelastic materials to the twin-free normal state. The transitions are characterized through order parameters (Rao Rao, 1978). These order parameters are characteristic properties parametrized in such a way that the resulting quantity is unity for the ferroic state at a temperature sufficiently below the transition temperature, and is zero in the nonferroic phase beyond the transition temperature. Polarization, magnetization and strain are the proper order parameters for the ferroelectric. 

Such so-called spin-exchange collisions may be experimentally distinguished only if the experiment involves measurement of differences due to spin interactions. For instance, collision cross-sections for eq. (6-5) might be measured with crossed molecular beams using spin polarizing magnetic fields. 

A schematic view of the nanomechanical GMR device to be considered is presented in Fig. 1. Two fully spin-polarized magnets with fully spin-polarized electrons serve as source and drain electrodes in a tunneling device. In this paper we will consider the situation when the electrodes have exactly opposite polarization. A mechanically movable quantum dot (described by a time-dependent displacement x(t)), where a single energy level is available for electrons, performs forced harmonic oscillations with period T = 2-k/uj between the leads. The external magnetic field is perpendicular to the orientation of the magnetization in both leads. 

In the absence of external fields the suspension under consideration is macroscopically isotropic (W = const). The applied field h (we denote it in the same way as above but imply the electric field and dipoles as well as the magnetic ones), orienting, statically or dynamically, the particles, thus induces a uniaxial anisotropy, which is conventionally characterized by the orientational order parameter tensor (Piin h)) defined by Eq. (4.358). (We remind the reader that for rigid dipolar particles there is no difference between the unit vectors e and .) As in the case of the internal order parameter S2, [see Eq. (4.81)], one may define the set of quantities (Pi(n h)) for an arbitrary l. Of those, the first statistical moment (Pi) is proportional to the polarization (magnetization) of the medium, and the moments with / > 2, although not having meanings of directly observable quantities, determine those via the chain-linked set [see Eq. (4.369)]. 

Here the inhomogeneous polarizing magnetic field points in z direction, and the spatial inhomogeneity in x direction has been expanded into a Taylor series and truncated after the second term. The first term of this series is the homogeneous field B(), the second one is the field gradient Gx = dBJdx)x=0 in x direction. 

De Nadai C, van der Laan G, Dhesi SS et al (2003) Spin-polarized magnetic circular dichroism in Ni 2p core-level photoemission. Phys Rev B 68 212401... 

If the direction of current flow in the coil is reversed, so is the direction of the magnetic field. And if the current is oscillating (i.e., alternating current), the resulting linearly polarized magnetic field will oscillate (change directions) at the same frequency (Figure 3.2). 

Figure 3.2. Orientation and magnitude of a linearly polarized magnetic field B as a function of the ac voltage in the loop of wire. The voltage follows the cosine curve shown below.

Resonance frequencies of nuclei in a polarizing magnetic field of strength corresponding to a proton resonance in TMS of exactly 100 MHz... 

Statistical Perturbation Calculus.—Statistical Mean Value. Let Q denote some physical quantity (electric polarization, magnetic polarization, exs,t%y), in general a function of the continuously varying canonic variables F (generalized momeita, generalized co-orclassical statistical mechanics, the mean value of Q is defined as ... 

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