Magnetic thermometry

The low-temperature limit of magnetic thermometry with paramagnetic salts (see Section 9.9) is given by the ordering temperature of the electronic magnetic moments. Such ordering temperature is around 1 mK (example the CMN thermometer). 

For a lower temperature thermometry, one has to move from electronic paramagnets to nuclear paramagnets. Magnetic thermometry with nuclear paramagnets extends the range of thermometry down to a few microkelvin. 

Nuclear magnetic thermometry is fundamental for the microkelvin range, but at higher temperatures the signal can be rather weak and may be overcome by contributions from electronic magnetic impurities. For the methods of detection of nuclear magnetization, see e.g. ref. [2],... 

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

Magnetic thermometry has been developed chiefly to measure temperatures near absolute zero (below -458°F, or -272°C). These measurements are obtained by adiabatic demagnetization of a paramagnetic salt. Inductance can be measured with an AC bridge (as shown in Figure 3.164) whose balance is independent of frequency. The relationship between self-inductance and sus-... 

This comprehensive review of theoretical models and techniques will be invaluable to theorists and experimentalists in the fields of infrared and Raman spectroscopy, nuclear magnetic resonance, electron spin resonance and flame thermometry. It will also be useful to graduate students of molecular dynamics and spectroscopy. 

An interesting aspect of dielectric constant thermometry is the small influence of a magnetic field. On the other hand, measurements depend on both the measuring frequency and voltage (see Figs 9.12 and 9.13). Figure 9.13 shows an example of the dependence on frequency of both the dielectric constant and loss for Upilex S [93]. 

Peters RD, Chan E, Trachtenberg J, Jothy S, Kapusta L, Kucharczyk W, Henkelman RM (2000) Magnetic resonance thermometry for predicting thermal damage an application of interstitial laser coagulation in an in vivo canine prostate model [In Process Citation]. Magn Reson Med 44 873... 

Fig. 14 Glioblastoma recurrence. (a,b) Pre-treatment brain magnetic resonance imaging (MRI). (c,d) Post-instillation computerised tomography (CT) showing magnetic nanoparticle deposits as hyperdense areas. Isothermal lines indicate calculated treatment temperatures between 40 °C (blue) and 50 °C (red). The brown line represents the tumour area. (e,f) 3-D reconstruction of fused MRI and CT showing the tumour (browri), magnetic fluid (blue) and thermometry catheter (greeri). Reprinted from Ref. 26 with kind permission from Springer Science -I- Business Media.

Chemical Thermodynamics Cryogenic Process Engineering Magnetic Materials Quantum Theory Statistical Mechanics Superconductivity Thermometry... 

Advantages of this type of thermometry are that it is sensitive, can have good time response, is not affected by magnetic fields, and needs no calibration. The primary disadvantage is that it can be used only between the triple point and critical point of the fill liquid. 

Carbon. The carbon resistance thermometer (CRT) has maintained its popularity in the field because it continues to provide high sensitivity at low temperatures in a low-cost, very small package. Carbon in one form or another is perhaps the most widely used of the high-resistivity materials for low-temperature thermometry, especially in the presence of magnetic fields. 

Vapor pressure and gas thermometry offer sensitive methods of temperature measurement with the advantage that no calibration is necessary. Further advantages are that these transducers are not sensitive to magnetic fields or electric fields. In the case of vapor pressure thermometers, the time response may be made comparable to the resistance thermometers. 

---