Susceptibility Curie

Magnetic thermometry 1. Electron paramagnetism 0 001-35 Magnetic susceptibility Curie s law plus corrections l/k T plus corrections ... 

Bae] Temperature dependence of magnetic susceptibility Curie temperature... 

Curie-Weiss law The molar magnetic susceptibility of a substance may be represented... 

Equation (A2.5.20) is the Curie-Weiss law, and the temperature at which the magnetic susceptibility becomes infinite, is the Curie temperature. Below this temperature the substance shows spontaneous magnetization and is ferromagnetic. Nonnally the Curie temperature lies between 1 and 10 K. However, typical ferromagnetic materials like iron have very much larger values for quantum-mechanical reasons that will not be pursued here. 

The molar diamagnetic susceptibility of thiazole and some derivatives was initially determined by the classical Curie-Cheneveau method (5,315,316) and later confirmed by a method (317) based on the difference of NMR proton chemical shift of a sample of tetramethylsilane immersed in the liquid to be investigated, according to the shape (cylindrical or spherical) of the sample tube (Table 1-47) (318),... 

ESR can detect unpaired electrons. Therefore, the measurement has been often used for the studies of radicals. It is also useful to study metallic or semiconducting materials since unpaired electrons play an important role in electric conduction. The information from ESR measurements is the spin susceptibility, the spin relaxation time and other electronic states of a sample. It has been well known that the spin susceptibility of the conduction electrons in metallic or semimetallic samples does not depend on temperature (so called Pauli susceptibility), while that of the localised electrons is dependent on temperature as described by Curie law. 

Magnetic measurements of PuFi, between 4.2 and 300 K are consistent at high temperatures with older measurements (10-12). The large temperature dependent diamagnetism observed earlier was not found. Up to 100 K the susceptibility is nearly temperature independent with a value of X ip 2940 x 10-6 emu. The Curie-Weiss behavior near room temperature indicates population of a higher first excited state. The structure of PuFi, is isomorphic with that of UFi, (13), where two different sets of actinide atoms are 8-fold coordinated by a distorted antiprism. 

Magnetic Susceptibilities. The magnetic susceptibilities of both plutonium compounds (Figure 3) show a weak Curie-Weiss paramagnetism for R, peff=0.87uB, 0=2.6°K9 and for P, Ueff=0.52jj]j,... 

Insofar that Curie s law is true, /left is independent of temperature, for that is how we arrived at Eq. (5.5). In practice. Curie s law is rarely obeyed exactly and, occasionally, it is quite seriously flouted. Nevertheless it is still conventional to quote /ieff values but it is then necessary to quote them over a range of temperatures. Although we might just as well report susceptibility values in these circumstances, conventions die hard. In any case, the temperature variation for /ieff immediately and transparently reveals any departures from Curie s Law in a way that the temperature variation of susceptibilities might not. 

The majority of octahedral ferric complexes exhibit simple Curie or Curie-Weiss magnetic behavior (i.e., magnetic susceptibility 1/7. They can be classified as either "high spin or "low spin. In high-spin complexes, the lowest term (ground state) is Aig, which corresponds to the tag eg2 configuration. The low-spin complexes have the Tgg term as... 

At room temperature, osmium hexafluoride yields a blue material of approximate composition CgOsFg (B22). Its magnetic susceptibility obeys the Curie-Weiss law, with a magnetic moment, /lefi = 3.5 BM,... 

Compound Band gap (eV) Ref. Magnetic susceptibility ref Curie point (°C) Ref... 

Exposure to low doses of radiation causes no short-term damage but makes the body more susceptible to cancers. In particular, people who have been exposed to increased radiation levels have a much higher incidence of leukemia than the general population has. Marie Curie, the discoverer of radium, eventually died of leukemia brought on by exposure to radiation in the course of her experiments. Medical researchers estimate that about 10% of all cancers are caused by exposure to high-energy radiation. 

The temperature dependence of the molar susceptibility of a paramagnetic substance follows the Curie-Weiss law (if the magnetic field is not too strong) ... 

A plot of the reciprocal of the measured susceptibility 1 /imol v.v. T is a straight line with slope 1/C, and which crosses the abscissa at T = 0 (Fig. 19.6). For 0 = 0 the equation is simplified to the classic Curie law mol = C/T. Generally, values of 0 (j arc found when cooperative effects arise at low temperatures (ferro-, ferri- or antiferromagnetism). The straight line then has to be extrapolated from high to low temperatures (dashed lines in Fig. 19.6). 

Above a critical temperature Tc, the Curie temperature, a ferromagnetic material becomes paramagnetic, since thermal motion inhibits the parallel orientation of the magnetic moments. The susceptibility then follows the Curie-Weiss law with a positive value of the Weiss constant, 0 > 0 (Fig. 19.6). 

At ordinary temperatures die magnetic susceptibility is given approximate This relation was determined experimentally by Piene Curie. Preach physicist... 

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