摘要:

Ferromagnetic resonance in thin films has been extended to the radio‐frequency region of from 1–20 Mc. Theoretical expressions governing this resonance condition are given along with experimental results. It is found that resonance in this region affords an excellent means of measuring the anisotropy fieldHk. Films with compositions near 80% Fe—20% Ni were studied by this technique. The anisotropy field of these films was found to be around 5 oe. The width of the absorption line varied from 0.6 to 2.4 oe, depending on the composition of the film. The minimum linewidth was found to occur for the composition of minimum magnetostriction.

ISSN:0021-8979    

DOI:10.1063/1.1728239

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

First‐order phase changes in shock‐loaded solids have been previously detected from the formation of multiple‐wave structures in the solids. It is shown theoretically that a multiple‐shock structure under shock loading also may be produced by a second‐order phase transition. Accordingly, the possibility of detecting shock‐induced demagnetization of ferromagnetic metals and alloys is discussed and an experimental attempt to detect such a demagnetization in shock‐loaded Invar (64 Fe, 36 Ni) is reported. Extrapolation of data by Patrick suggests a Curie point transition in Invar in the neighborhood of 50 kbar. The Hugoniot equation of state of Invar has been obtained over a pressure range of 35 to 160 kbar. No double‐shock structure was observed, but a decrease in compressibility observed in the neighborhood of 60 kbar is thought to be evidence of demagnetization.

ISSN:0021-8979    

DOI:10.1063/1.1728240

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Copper (99.999%) crystals with a dislocation density of 50/mm2have been prepared. These crystals were stressed by applying a pure bending moment, and they were etched with a dislocation etch either before and after or while the stress was applied. The motion of dislocations was determined by observing the size and nature of the dislocation etch pits. The resolved stress necessary to move grown‐in dislocations was about 4 g/mm2. Examples of dislocation motion under stress, then return motion when the stress was removed, and of multiple motion under stress were observed. Multiplication of dislocations occurred at a resolved stress of about 18 g/mm2. The observed phenomena are discussed in terms of simple dislocation theory.

ISSN:0021-8979    

DOI:10.1063/1.1728241

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The Czochralski method of pulling from the melt has been applied to the growth of single crystals of divalent fluorides of Ca, Sr, Ba, Co, and Mn, and the compound KMnF3. The trivalent rare earth ions Ce, Nd, Sm, Eu, Gd, Tb, and Yb were introduced into CaF2and the distribution coefficient was determined to be close to unity in all cases.

ISSN:0021-8979    

DOI:10.1063/1.1728242

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The electrical and optical properties ofn‐type germanium have been studied for doping levels greater than 5×1018cm−3. Hall coefficient and resistivity measurements show that the electron mobility &mgr; depends upon the specific group V donor used as a dopant and, at a given carrier concentration, increases in the order &mgr;As<&mgr;P<&mgr;Sb. In material doped very heavily with arsenic, a large fraction of the arsenic was found to be electrically inactive. Rapid quenching of this material resulted in larger carrier concentrations and a better correlation with crystal growth parameters. Distribution coefficients were calculated from the electrical measurements on antimony‐doped crystals grown by a solvent evaporation technique. No significant ``facet effect'' was observed for these crystals. Reflectivity measurements between 2 and 24 &mgr; were used to deduce the electron effective mass as a function of carrier concentration. In the carrier concentration range studied (up to 8×1019cm−3), the effective mass increases only slightly and is independent of the specific dopant. The free carrier absorption is dependent on dopant. The absorption and electrical data are correlated by using elementary conduction theory.

ISSN:0021-8979    

DOI:10.1063/1.1728243

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A calculation is made for the high‐power instability of theZ‐directed spin waves in a thin insulating ferromagnetic film. For complete pinning, the critical field is found to be(&ggr;h)2=&Dgr;n3n2&pgr;2[93(&ohgr;M+13&ohgr;exa2kn2)]−1.The calculation is also made for the critical field, assuming a mixed boundary condition.

ISSN:0021-8979    

DOI:10.1063/1.1728244

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A zone technique which should be applicable to many peritectic type compounds has been used to grow good‐quality single crystals of ZnSb. It consists here of moving a molten antimony‐rich zone along a charge of stoichiometric composition headed by some crystalline ZnSb.

ISSN:0021-8979    

DOI:10.1063/1.1728245

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Experimental verification of time‐average forces due to an rf field acting on charged particles is obtained by measuring the transmission of an electron beam through the high‐frequency fields of a cavity. By adjusting the external dc magnetic field so that cyclotron resonance is approached, it is possible to reflect high‐energy beams; that is, 66 w of microwave power completely reflected a 24‐v beam. Agreement between experiment and theory was close.

ISSN:0021-8979    

DOI:10.1063/1.1728246

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The properties of recombination centers introduced by reactor fast neutrons inn‐type germanium were investigated. From carrier lifetime temperature measurements, using Shockley‐Read statistics, recombination‐level position has been calculated and found to be dependent on resistivity of germanium. It has been observed for the first time that in the region of low temperature, lifetime increases with decreasing temperature.

ISSN:0021-8979    

DOI:10.1063/1.1728247

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Double diffraction of electrons by tandem foils of polycrystalline MgO and single crystal silicon is demonstrated. The patterns are very similar irrespective of which foil the electrons pass through first. The effect is explained by elastic bending of the thin, silicon crystal. The relationship between the double diffraction features, Kikuchi lines, and angular distortion of the crystal is discussed.

ISSN:0021-8979    

DOI:10.1063/1.1728248

出版商:AIP    

年代:1961

数据来源: AIP