Susceptibility alternating current

Six [Ln(Pc)2] complexes with heavy lanthanide ions (Ln = Tb, Dy, Ho, Er, Tm or Yb) were investigated by the measurements of alternating current (AC) magnetic susceptibility [18]. Out of the six compounds, [TbPc2] and [DyPc2] were found to show temperature and frequency dependence on AC magnetic susceptibility similar to that observed for the transition-metal SMMs, while the rest did not. Their SMM behaviour have been observed either in bulk, in dilute solid solutions... 

Figure 3.24. Alternating-current susceptibility versus temperature for different superimposed dc fields H = 0, 50, 100, 150, 200, 250 Oe. mjln = 125 Hz.

Figure 3.25. Alternating-current susceptibility versus time for different superimposed dc fields R = 40, 80, 120, 160, 200 Oe. co/2Tt = 510 Hz.

Susceptance — In alternating current (AC) electrical - immittance measurements, susceptance is the imaginary part of admittance given by ... 

Alternating current susceptibility [100,101] (AC susceptibility), xac, is the most widely used parameter to characterize the dynamic behavior of the relaxation system. The AC susceptibility is a function of the frequency of the alternating field, where the static field (which may be zero) is parallel to the AC field. ac is a complex value, combined from two parts, in-phase and out-of-phase. 

Electronic instruments are subject to instrumental systematic errors. These can have many sources. For example, errors may emerge as the voltage of a battery-operated power supply decreases with use. Errors can also occur if instruments are not calibrated frequently or calibrated incorrectly. The experimenter may also use an instrument under conditions in which errors are large. For example, a pH meter used in strongly acidic media is prone to an acid error, as discussed in Chapter 20. Temperature changes cause variation in many electronic components, which can lead to drifts and errors. Some instruments are susceptible to noise induced from the alternating current (ac) power lines, and this noise may influence precision and accuracy. In many cases, errors of these types are detectable and correctable. 

Since detailed experimental data for ferrofluid susceptibilities in a strong oblique polarizing field (of intensity 10 T and higher) superimposed on which is a weak alternating-current field are not yet readily available, we shall in Section III.E confine ourselves to an illustration of how the weak alternating-current field susceptibilities [Eqs. (Ill), (113), and (116), which incorporate the effect of the fluid carrier] compare favorably with experiment. We shall also demonstrate the effect that a weak polarizing field Ho (0 100 kA/m) has on the susceptibility profiles (Figs. 7, 8, and 9) below. Furthermore, we shall show how... 

Admittance A measure of how well alternating current flows in a conductor. It is the reciprocal of impedance and is expressed in siemens. The real part of admittance is conductance-, the imaginary part is susceptance. 

The Dy ion turns to be the core magnetic center in the molecule [Dy(hfac)3]2Cu(dpk)2/ where dpk = di-2-pyridyl ketoximate. On taking the alternative current susceptibility measurement from 2 to 17K at 50-10 000 Hz, both the in-phase and out-of-phase susceptibilities are found to be frequency dependent. The energy barrier fit from the Arrhenius plot is 47 K and t is 1.1 x 10 s. Additionally, Xm against Xm plotted at 8K from 50 to 10 000 Hz is a semicircle, which indicates that this is a single-relaxation process. 

Alternating current (ac) magnetic susceptibility measurements in zero dc field allow to probe slow magnetization relaxation indicating SMMs behaviour. The applied oscillating held probes the dynamics of this reorientation, as the out-of-... 

Despite these alternatives, there are a few patients who cannot tolerate stimulants or who may be susceptible to abusing them. In such cases, the alternatives are limited. The best treatments for poor attention (in lieu of the stimulants) are antidepressants that boost norepinephrine and/or dopamine activity in the brain. Currently, this includes the TCAs, MAOls, and possibly venlafaxine or duloxetine. 

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