Quantum galvanomagnetic and thermomagnetic effects in graphite to 18.3 teslas /180 kG/ at low temperatures
Quantum galvanomagnetic and thermomagnetic effects in graphite in magnetic fields at low temperatures
Woollam, J. A.↗
SEARCH · Search NASA
Results for “thermomagnetic effects”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Galvanomagnetic and thermomagnetic effects in white tin in fields to 3.3 tesla and at temperatures between 1.2 and 4.2 K
Nernst-Ettingshausen, thermoelectric power, thermal transverse-even, magnetoresistance, and Hall coefficients in white tin in 3.3 tesla field and cryogenic temperatures
Woollam, J. A.↗
Thermomagnetic effects and Fermi surface topology - Results in metallic tin at low temperatures.
Fermi surface topology effects on Nernst- Ettingshausen coefficient from measurements in magnetic fields to 3.3 tesla and 1.2-4.2 K temperatures in metallic tin
Woollam, J. A.↗
Transport processes in magnetosolidmechanics- adiabatic conditions.
Transport processes under adiabatic conditions between external magnetic field and thermal and electrical gradients in solid, defining galvanomagnetic and thermomagnetic effects
Arnas, O. A.↗
Is the 1.5-ms pulsar a young neutron star?
It is proposed that PSR1937 + 214 is a young neutron star spun up by accretion from a high-mass companion in a close binary system. The supercritical mass transfer rates expected in such a binary system should allow the neutron star to be spun up in the comparatively short time of about 10,000 yr. The accretion process will also power thermomagnetic effects that could remove the strong magnetic field of a young pulsar from the crust of the star in a similarly short timescale. Such a high-mass binary system is expected to disrupt when the companion explodes in a supernova. Thus a spin-up model in a high-mass system can explain the lack of a companion, low magnetic field, and high spin rate of PSR1937 + 214.
Blondin, John M.↗
Does mass accretion lead to field decay in neutron stars?
Adopting the hypothesis of accretion-induced magnetic field decay in neutron stars, the consequent evolution of a neutron star's spin and magnetic field are calculated. The results are consistent with observations of binary and millisecond radio pulsars. Thermomagnetic effects could provide a possible physical mechanism for such accretion-induced field decay.
Shibazaki, N.↗
Thermomagnetic torques in polyatomic gases
The application of the Scott effect to the dynamics of galactic and stellar rotation is investigated. Efforts were also made to improve the sensitivity and stability of torque measurements and understand the microscopic mechanism that causes the Scott effect.
Hildebrandt, A. F.↗
Microwave resonance thermomagnetic analysis - A new method for characterizing fine-grained ferromagnetic constituents in lunar materials
Microwave resonance thermomagnetic analysis (MRTA) is the name given to a newly evolved technique for inferring the natures of fine-grained ferromagnetic constituents in lunar materials. Based on standard ferromagnetic resonance (FMR) procedures, the method makes use of the microwave skin effect for diagnosing the presence of metallic iron. Modelling experiments carried out on well-characterized iron and magnetitelike precipitates produced independently in simulated lunar glasses, coupled with published data for magnetite, provide a potential basis for detecting and discriminating between iron metal and ferric iron spinel, even when both are present in an unknown sample. Application of the technique to the lunar samples indicates the possible existence of magnetitelike phases in amounts up to about 0.3 wt% in soils from seven samples regions of the moon. These findings do not require any special geologic processes for their explanation, although some evidence supports the suggestion that fumarolic activity may have occurred in the lunar highlands.
Griscom, D. L.↗
Thermomagnetic phenomena in the mixed state of high temperature superconductors
Galvano- and thermomagnetic-phenomena in high temperature superconductors, based on kinetic coefficients, are discussed, along with a connection between the electric field and the heat flow in superconductor mixed state. The relationship that determines the transport coefficients of high temperature superconductors in the mixed state based on Seebeck and Nernst effects is developed. It is shown that this relationship is true for a whole transition region of the resistive mixed state of a superconductor. Peltier, Ettingshausen and Righi-Leduc effects associated with heat conductivity as related to high temperature superconductors are also addressed.
Meilikhov, E. Z.↗
Shape, size, and distribution of magnetic particles in Bjurbole chondrules
Chondrules from the Bjurbole chondritic meteorite (L4) exhibit saturation remanence magnetization (SIRM) values which vary over three orders of magnitude. REM values (Natural Remanence Magnetization/SIRM) for Allende (C3V) and Chainpur (LL3) are less than 0.01 but in Bjurbole some chondrules were found to have REM values greater than 0.1 with several greater than 0.2. REM values greater than 0.1 are abnormal and cannot be acquired during weak field cooling. If exposure to a strong field (whatever the source) during the chondrules' history is responsible for the high REM values, was such history associated with a different processing which might have resulted in different shape, size, and distribution of metal particles compared to chondrules having REM values of less than 0.01? Furthermore, magnetic hysteresis results show a broad range of magnetic hardness and other intrinsic magnetic properties. These features must be related to (1) size and amount of metal; and (2) properties of, and amount of, tetrataenite in the chondrules (all chondrules thus far subjected to thermomagnetic analysis show the presence of tetrataenite). A scanning electron microscopy (SEM) study is underway to determine the relationship between the shape, size, and distribution of metal particles within individual chondrules and the magnetic properties of these chondrules. Results from the SEM study in conjunction with magnetic property data may also help to discern effects from possible lightning strikes in the nebula prior to incorporation of the chondrules into the parent body.
Nava, David F.↗
Magnetic cristobalite (?) - A possible new magnetic phase produced by the thermal decomposition of nontronite
The effect of heat treatment for 1 h or more at 900-1000 C on the magnetic properties of nontronite, an iron-rich smectite clay thought to be an important component of Martian regolith, is investigated experimentally, extending the findings of Moskowitz and Hargraves (1982). The results are presented in graphs and tables and discussed. A phase with Curie temperature 200-220 C, remanent coercivity greater than 800 mT, and a type-2 room-temperature-coercivity response to thermomagnetic cycling is observed and attributed to an iron-substituted cristobalite which may form by topotactic growth from a smectite precursor.
Moskowitz, B. M.↗
Thermomagnetic recording and magneto-optic playback system having constant intensity laser beam control
A system is developed for maintaining the intensity of a laser beam at a constant level in a thermomagnetic recording and magneto-optic playback system in which an isotropic film is heated along a continuous path by the laser beam for recording. As each successive area of the path is heated locally to the vicinity of its Curie point in the presence of a controlled magnetic field, a magneto-optic density is produced proportional to the amplitude of the controlled magnetic field. To play back the recorded signal, the intensity of the laser beam is reduced and a Faraday or Kerr effect analyzer is used, with a photodetector, as a transducer for producing an output signal.
Lewicki, G. W.↗
Thermomagnetic recording and magnetic-optic playback system
A magnetic recording and magneto-optic playback system is disclosed wherein thermomagnetic recording is employed. A transparent isotropic film is heated along a continuous path by a focused laser beam. As each successive area of the path is heated locally to the vicinity of its Curie point in the presence of an applied magnetic field, a magneto-optic density is established proportional to the magnetic field and fixed in place as the area cools once the laser beam moves on to an adjacent area. To play back the recorded data, the intensity of the laser beam is reduced to avoid reaching the vicinity of the Curie point of the film as it is scanned by the laser beam in the same manner as for recording. A Faraday effect analyzer and photo detector are employed as a transducer for producing an output signal.
Lewicki, G. W.↗