Linewidth temperature dependence

CNTs are purified by oxidizing the crude ones as prepared. During the oxidation process, the nanoparticles are removed gradually and eventually only open CNTs remain [9]. An intrinsic CESR was observed from these purified COTs [12]. The temperature dependencies of susceptibility, linewidth and g-value of the CESR are shown in Fig. 2 (open circle). We find a temperature independent spin susceptibility (Pauli) = 4.3 x 10 emu/g. 

Fig. 2. Temperature dependencies of spin susceptibilities, linewidths and g-values of the CESR for the purified CNTs (open circle) and the annealed purified CNTs (solid circle).

The samples remained crack-free during cooling to the temperature of liquid helium. In the range between 1.1 K and 3.94 K an algebraic temperature dependence 7 with a = 1.25 0.1 was found for the linewidth (FWHM) of the trapped dye. At 3.94 K the linewidth was 2.10 GHz. This is about... 

FIGURE 4.2 Linewidth increase with temperature for an S = 1/2 system. The linewidth of a feature in the low-spin heme spectrum from cytochrome a in bovine heart cytochrome oxidase has been fit as a convolution of a constant component from inhomogeneous broadening and a temperature-dependent component from homogeneous broadening (Hagen 2006). (Reproduced by permission of The Royal Society of Chemistry.)... 

The temperature dependencies of the soft mode frequency (closed symbols) and spectral linewidths (open symbols) in ST016, ST018-23, and ST018-32 are presented in Fig. 17a-c [27]. The crosses in Fig. 17a denote the temperature dependence of the soft mode frequency observed by hyper-Raman scattering. The results shown in Fig. 17 clearly indicate a decrease in... 

The EPR of a Mn2+ impurity in mixed crystal N ClajIm has been observed38 between X-band and 250 GHz. Spectra from three magnetically inequivalent, but physically equivalent, Mn2+ ions were observed. The temperature dependence of the linewidth revealed phase transitions at 228 K and 242 K. The analysis of all the spectra was consistent with a model of an axially symmetric crystal field... 

Mossbauer spectroscopy can only be used to obtain rates of interconversion if the lifetimes are close to 10 7 second. As described in Section III,E a few examples satisfying this condition have been found. Some questions remain over the quantitative interpretation of the data. Nevertheless, spin-equilibrium relaxation lifetimes have been estimated from Mossbauer temperature-dependent linewidths for two salts of an iron(III) complex, [Fe(acpa)2]+. The lifetimes are of the order 10 5—10 7 second over temperature ranges from 100 to 300 K (109, 111). 

The occurrence of this particular relaxation mechanism can be recognized through the field and temperature dependence of the linewidths. In the absence of other effects, the line broadening is proportional to the square of the magnetic field... 

No explicit temperature dependence is included in the equations for R m and Rim, except for cases where Curie spin relaxation is the dominant term (Section 3.6). In the latter case, Curie paramagnetism has a T x dependence and therefore relaxation depends on T 2. The effect of temperature on linewidths determined by Curie relaxation is dramatic also because of the xr dependence on temperature, as shown in Eq. (3.8). All the correlation times modulating the electron-nucleus coupling, either contact or dipolar, are generally temperature dependent, although in different ways, and their variation will therefore be reflected in the values of Rim and Rim-... 

Figure 111 1 3. Temperature dependence of the peak-to-peak linewidth AHpp for the narrow and broad EPR lines in La2 xSrxCuo 98Mn0 0204 with x=0.01, 0.02 and 0.03...

Figure 111 1 3. Temperature dependence of the peak-to-peak linewidth AHpp for the...

Cu(phen), Fig.3c. g-factor components values are close to these for preceding compounds, they are gy = 2.34 and g = 2.07. Their temperature dependence is absent. The resonance linewidth have appreciable weak temperature dependence in comparison with preceding compounds. 

The reduction of exchange interactions from Cu(en) to Co(phen) compound in investigated series is evident from results of Table 2. The temperature dependence of the linewidth correlates well with this sequence. 

A series of SPR spectra of a borate glass sample annealed at 753 K are recorded at measurement temperatures Tm from 300 to 723 K, figure 5. The corresponding temperature dependence of the peak-to-peak linewidth are shown in figure 6. As Tm is increased, a drastic line narrowing occurs,... 

Figure 8 shows the temperature dependence of the apparent resonance field 7 apparent cf. eq. (19), and the apparent peak-to-peak linewidth. The spectra broadening and shift towards lower fields with the decrease in temperature are clearly seen. (A weak resonance at geff 4.3 is due to a... 

Figure 8. Temperature dependence of the apparent resonance field (top) and of the peak-to-peak linewidth (bottom) in the experimental and computer-simulated spectra. The full curve in the left part is the dependence of apparent given by eq. (19), and that in the right part shows the theoretical Ar (T) dependence of eq. (21).

The temperature dependence of the individual linewidth, eq. (21), is rather complicated. At very low temperatures the Langevin function in this equation becomes saturated for the majority of the nanoparticles, so that the main mechanism of this dependence is the thermal modulation of the magnetic anisotropy energy. Indeed, one can see from figure 8 (bottom) that the Ar temperature dependence provides a good estimate of the experimental low-temperature linewidth. As the damping factor linearly depends on the linewidth, it follows the same temperature dependence [11],... 

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