Magnetic history

If one assumes A to be a constant, then (3) defines an effective inductance which is proportional to the values found in Fig. 4b. It is known p] that the inductance of superconducting coils varies considerably below about 20 kgauss, but this plot also shows the strong dependence on the magnetic history of the coil. It may be mentioned here that this behavior of the coil is quite reproducible within the error limits. However, immediately following a breakdown of superconductivity (critical field exceeded), the reproducibility becomes very poor. 

The Gaussian shape of the additional relaxation indicates the development of a strongly disordered magnetic state with moments around 0.03 jUg- The authors note that the onset of this relaxation corresponds to the appearance of a broad and sizeable anomaly in specific heat (Furuno et al. 1988) and to the development of flie dependence of x on magnetic history. 

The result of efforts in (a-c) is shown in Figure 2. Care was taken with respect to temperature effects, electromagnetic noise, and stability of the electronic components. Additionally, the vials speed and consequently the magnetic history are essential parameters to be considered in the measuring sequoice. 

Van Vleck, J.H., 1965, The magnetic history of rare earths, in Rare Earth Research, Vol. Ill, ed. L. Eyring (Gordon and Breach, New York) p. 3. 

ITie two most commonly magnetic histories used in experiments are the following (Tholence and Tournier 1974) the zero-field-cooled (ZFC) magnetization is obtained by cooling the sample to the measuring temperature T < in zero external field starting at high temperature T>T then a field H is applied at T and M is measured After this ZFC procedure one can switch off the... 

We now turn to the remanent magnetization which is only a small part of the total magnetization and is dependent on magnetic history, too, with... 

The ac-susceptibility as discussed later only measures the reversible part Xrtv Equations (38) to (40) are consistent with the following relation (Maletta 1980c) between the magnetizations and remanent magnetizations measured after different magnetic histories, as is obvious from fig. 23, too ... 

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