Determination of angular dependence of the critical field of barium ferrite from remanence and microwave measurements (abstract)

1988 ◽  
Vol 64 (10) ◽  
pp. 6000-6000 ◽  
Author(s):  
F. Schumacher ◽  
K. A. Hempel ◽  
F. von Staa
Keyword(s):  
Angular Dependence ◽  
Critical Field ◽  
Barium Ferrite ◽  
Microwave Measurements

scholarly journals Multiband effects on the upper critical field angular dependence of 122-family iron pnictide superconductors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
I. F. Llovo ◽  
C. Carballeira ◽  
D. Sóñora ◽  
A. Pereiro ◽  
J. J. Ponte ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Angular Dependence ◽  
Critical Field ◽  
Upper Critical Field ◽  
Single Band ◽  
Band Model ◽  
Cooper Pairs ◽  
Ginzburg Landau ◽  
Superconducting Fluctuations

AbstractDetailed measurements of the in-plane resistivity were performed in a high-quality Ba($$\hbox {Fe}_{1-x}\hbox {Co}_{{x}}$$ Fe 1 - x Co x )$$_2\hbox {As}_2$$ 2 As 2 ($$x=0.065$$ x = 0.065 ) single crystal, in magnetic fields up to 9 T and with different orientations $$\theta$$ θ relative to the crystal c axis. A significant $$\rho (T)_{H,\theta }$$ ρ ( T ) H , θ rounding is observed just above the superconducting critical temperature $$T_c$$ T c due to Cooper pairs created by superconducting fluctuations. These data are analyzed in terms of a generalization of the Aslamazov-Larkin approach, that extends its applicability to high reduced-temperatures and magnetic fields. This method allows us to carry out a criterion-independent determination of the angular dependence of the upper critical field, $$H_{c2}(\theta )$$ H c 2 ( θ ) . In spite of the relatively small anisotropy of this compound, it is found that $$H_{c2}(\theta )$$ H c 2 ( θ ) presents a significant deviation from the single-band 3D anisotropic Ginzburg-Landau (3D-aGL) approach, particularly for large $$\theta$$ θ (typically above $$\sim 60^o$$ ∼ 60 o ). These results are interpreted in terms of the multiband nature of these materials, in contrast with other proposals for similar $$H_{c2}(\theta )$$ H c 2 ( θ ) anomalies. Our results are also consistent with an effective anisotropy factor almost temperature independent near $$T_c$$ T c , a result that differs from the ones obtained by using a single-band model.

On the angular dependence of the upper critical field in thin films

1966 ◽  
Vol 20 (2) ◽  
pp. 122-123 ◽  
Author(s):  
K. Yamafuji ◽  
T. Kawashima ◽  
F. Irie
Keyword(s):  
Thin Films ◽  
Angular Dependence ◽  
Critical Field ◽  
Upper Critical Field

scholarly journals Characterization and Application of a Grazing Angle Objective for Quantitative Infrared Reflection Microspectroscopy

1995 ◽  
Vol 49 (3) ◽  
pp. 354-360 ◽  
Author(s):  
Stephen V. Pepper
Keyword(s):  
Angular Dependence ◽  
Grazing Angle ◽  
Fresnel Reflection ◽  
Angular Aperture ◽  
Incident Intensity ◽  
Specular Reflectance ◽  
Fresnel Reflection Coefficient ◽  
Infrared Reflection ◽  
Good Agreement

A grazing angle objective on an infrared microspectrometer is studied for quantitative spectroscopy by considering the angular dependence of the incident intensity within the objective's angular aperture. The assumption that there is no angular dependence is tested by comparing the experimental reflectance of Si and KBr surfaces with the reflectance calculated by integrating the Fresnel reflection coefficient over the angular aperture under this assumption. Good agreement was found, indicating that the specular reflectance of surfaces can straightforwardly be quantitatively integrated over the angular aperture without considering nonuniform incident intensity. This quantitative approach is applied to the thickness determination of dipcoated Krytox on gold. The infrared optical constants of both materials are known, allowing the integration to be carried out. The thickness obtained is in fair agreement with the value determined by ellipsometry in the visible. Therefore, this paper illustrates a method for more quantitative use of a grazing angle objective for infrared reflectance microspectroscopy.

The Determination of the Molecular Structure of Bromosilane by Microwave Measurements

1949 ◽  
Vol 76 (9) ◽  
pp. 1419-1419 ◽  
Author(s):  
A. H. Sharbaugh ◽  
J. K. Bragg ◽  
T. C. Madison ◽  
V. G. Thomas
Keyword(s):  
Molecular Structure ◽  
Microwave Measurements

Experimental determination of the upper critical field of epitaxially grown thin films of YBa2Cu3O7−δdown to He temperature

1991 ◽  
Vol 70 (4) ◽  
pp. 2230-2233 ◽  
Author(s):  
R. Wördenweber ◽  
M. O. Abd‐El‐Hamed ◽  
J. Schneider ◽  
O. Laborde
Keyword(s):  
Thin Films ◽  
Experimental Determination ◽  
Critical Field ◽  
Upper Critical Field
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