scholarly journals Direct measurement of the three-dimensional magnetization vector trajectory in GaMnAs by a magneto-optical pump-and-probe method

2012 ◽  
Vol 100 (10) ◽  
pp. 102403 ◽  
Author(s):  
N. Tesařová ◽  
P. Němec ◽  
E. Rozkotová ◽  
J. Šubrt ◽  
H. Reichlová ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Three Dimensional ◽  
Magnetization Vector ◽  
Probe Method ◽  
Optical Pump ◽  
Pump And Probe

Excitation and detection of coherent optical phonon modes in epitaxial cubic Ge2Sb2Te5thin films of different crystallographic orientation

2014 ◽  
Vol 1661 ◽  
Author(s):  
R. Al-Saigh ◽  
A. Shalini ◽  
G. P. Srivastava ◽  
R. J. Hicken ◽  
R. Calarco
Keyword(s):  
Data Storage ◽  
Rock Salt ◽  
Optical Phonon ◽  
Three Dimensional ◽  
Signal Amplitude ◽  
Phonon Modes ◽  
Rock Salt Structure ◽  
Optical Pump ◽  
Pump And Probe ◽  
Salt Structure

ABSTRACTOptical pump-probe studies of cubic crystalline Ge2Sb2Te5/GaSb(001) have previously shown that the amplitude of a coherent optical phonon (COP) with frequency of 3.4 THz observed in the anisotropic reflectance (AR) signal exhibits a four-fold dependence upon the polarization of the probe beam. The appearance of the mode in the AR signal but not the reflectance (R) signal, and the dependence upon probe polarization, both suggest a three-dimensional mode character. Confirmation that this mode indeed has three-dimensional character, similar to the Raman inactive T2 mode in the pristine rock salt structure, is highly important in understanding the structure of the crystalline phase of Ge2Sb2Te5 that has important applications within data storage technology. A phonon of the same frequency has been observed in an epitaxial Ge2Sb2Te5/InAs(111) structure, suggesting that this phonon is indeed characteristic of epitaxial cubic GST. A theory, which considers the symmetry of the Raman tensor for a particular phonon mode, is used to predict the dependence of R and AR signal amplitude upon pump and probe polarization for the T2 mode of a (111) facet of the putative rock-salt structure.

Simulation of multiwavelength conditions in laser picosecond ultrasonics

SIMULATION ◽  
2021 ◽  
pp. 003754972199645
Author(s):  
Philippe Babilotte
Keyword(s):  
Numerical Simulations ◽  
Acoustic Signal ◽  
Acoustic Waves ◽  
Bulk Material ◽  
Deformation Field ◽  
Optical Pump ◽  
Pump And Probe ◽  
Oriented Object ◽  
Numerical Approaches ◽  
Picosecond Ultrasonics

Complete numerical simulations are given under SciLab® and MATLAB® coding environments, concerning propagative acoustic wavefronts, for laser picosecond ultrasonics under multiwavelength conditions. Simulations of the deformation field and its propagation into bulk material are given under different wavelength configurations for optical pump and probe beams, which are used to generate and to detect the acoustic signal. Complete insights concerning the dynamics of the acoustic waves are given, considering the absence of carrier diffusions into the material. Several numerical approaches are proposed concerning both the functions introduced to simulate the wavefront ( Heaviside or error) and the coding approach (linear/vectorized/ Oriented Object Programming), under the pure thermo-elastic approach.

Optical pump-and-probe measurement of the thermal conductivity of nitride thin films

2002 ◽  
Vol 92 (7) ◽  
pp. 3820-3824 ◽  
Author(s):  
B. C. Daly ◽  
H. J. Maris ◽  
A. V. Nurmikko ◽  
M. Kuball ◽  
J. Han
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Probe Measurement ◽  
Optical Pump ◽  
Pump And Probe

Anomaly of Thermal Properties in Thin Films of La1-x SrxCoO3 Series Fabricated as Thermoelectric Materials

2002 ◽  
Vol 730 ◽  
Author(s):  
Yoshiaki Takata ◽  
Hajime Haneda ◽  
Yutaka Adachi ◽  
Yoshiki Wada ◽  
Takefumi Mitsuhashi ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Thermoelectric Materials ◽  
Signal Analysis ◽  
Material Synthesis ◽  
Thermo Electric ◽  
Optical Pump ◽  
Pump And Probe ◽  
Reflection Geometry

AbstractComposition spreads of La1-xSrxCoO3 (LSCO) were synthesized as thermo-electric transducer material by means of combinatorial material synthesis, and information on their thermal diffusivity throughout the specimens was obtained. Meanwhile, it is anticipated that the composition spreads of LSCO have a variety of characteristic properties of light absorption corresponding to their composition, namely their compositional variable, x. Hence, we used transient optical pump-and-probe techniques in a reflection geometry to measure thermal diffusion times on LSCO. The results of signal analysis indicate that LSCO is a peculiar synthesized substance whose apparent thermal diffusivity, 1/ι, changes abruptly at the critical point, where the compositional variable x is equal to 0.3.

Comprehensive approaches to 3D inversion of magnetic data affected by remanent magnetization

Geophysics ◽  
2010 ◽  
Vol 75 (1) ◽  
pp. L1-L11 ◽  
Author(s):  
Yaoguo Li ◽  
Sarah E. Shearer ◽  
Matthew M. Haney ◽  
Neal Dannemiller
Keyword(s):  
Mineral Exploration ◽  
Three Dimensional ◽  
Canadian Arctic ◽  
Magnetization Vector ◽  
Magnetic Data ◽  
Inversion Algorithm ◽  
3D Inversion ◽  
Magnetization Direction ◽  
Direct Inversion ◽  
Amplitude Data

Three-dimensional (3D) inversion of magnetic data to recover a distribution of magnetic susceptibility has been successfully used for mineral exploration during the last decade. However, the unknown direction of magnetization has limited the use of this technique when significant remanence is present. We have developed a comprehensive methodology for solving this problem by examining two classes of approaches and have formulated a suite of methods of practical utility. The first class focuses on estimating total magnetization direction and then incorporating the resultant direction into an inversion algorithm that assumes a known direction. The second class focuses on direct inversion of the amplitude of the magnetic anomaly vector. Amplitude data depend weakly upon magnetization direction and are amenable to direct inversion for the magnitude of magnetization vector in 3D subsurface. Two sets of high-resolution aeromagnetic data acquired for diamond exploration in the Canadian Arctic are used to illustrate the methods’ usefulness.

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