Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/309
G. Brown, J. Thorp
Spin-lattice relaxation times in ruby and sapphire have been measured at 35 and 70 Gc/s by a pulse-response technique using a grid-modulated reflex klystron, the peak pulse power at the specimen being about 10 μW. Relaxation times at 42°K covering the range from 2 msec to 24 msec have been measured at 35 Gc/s, the results in each case agreeing with those obtained from pulse-saturation measurements on the same specimens. Preliminary data are given of the relaxation in ruby at 70 Gc/s, the microwave power being obtained by harmonic generation from 35 Gc/s. The range of applicability of the method is discussed.
{"title":"The measurement of spin-lattice relaxation times at very low power levels","authors":"G. Brown, J. Thorp","doi":"10.1088/0508-3443/18/10/309","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/309","url":null,"abstract":"Spin-lattice relaxation times in ruby and sapphire have been measured at 35 and 70 Gc/s by a pulse-response technique using a grid-modulated reflex klystron, the peak pulse power at the specimen being about 10 μW. Relaxation times at 42°K covering the range from 2 msec to 24 msec have been measured at 35 Gc/s, the results in each case agreeing with those obtained from pulse-saturation measurements on the same specimens. Preliminary data are given of the relaxation in ruby at 70 Gc/s, the microwave power being obtained by harmonic generation from 35 Gc/s. The range of applicability of the method is discussed.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"36 1","pages":"1423-1430"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72803500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/313
R. Calder, G. Lewin
The outgassing rate of a 2 mm thick stainless-steel sheet was measured in ultra-high vacuum at constant pressure to avoid the readsorption occurring in a `rate of pressure rise' determination. The rate was typically 10-12 torr l. cm-2 sec-1 and about 99% or more of the gas was hydrogen. Since stainless steel usually contains large amounts of hydrogen and the diffusion coefficient of hydrogen in stainless steel is high, it was suspected that the hydrogen diffuses to the surface from the interior of the metal and is released into the vacuum. Calculations show that the observed outgassing rate could be explained by such a process and should be reduced by several orders of magnitude by a high-temperature treatment. The effects of residual hydrogen in the treatment furnace and hydrogen permeation from the atmosphere are also considered in these calculations. The greater the thickness of the metal, the higher the temperature has to be. Measurements are in reasonable agreement with these calculations.
在超高真空和恒压条件下测量2mm厚不锈钢板的放气速率，以避免在“压力上升速率”测定中发生再吸附。速率通常为10-12 torr l. cm-2 sec-1，大约99%或更多的气体是氢气。由于不锈钢通常含有大量的氢，并且氢在不锈钢中的扩散系数很高，因此怀疑氢是从金属内部扩散到表面并释放到真空中。计算表明，观察到的放气速率可以用这种过程来解释，并且通过高温处理可以降低几个数量级。在这些计算中还考虑了处理炉内残余氢和大气中氢渗透的影响。金属的厚度越大，温度就必须越高。测量结果与这些计算结果相当吻合。
{"title":"Reduction of stainless-steel outgassing in ultra-high vacuum","authors":"R. Calder, G. Lewin","doi":"10.1088/0508-3443/18/10/313","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/313","url":null,"abstract":"The outgassing rate of a 2 mm thick stainless-steel sheet was measured in ultra-high vacuum at constant pressure to avoid the readsorption occurring in a `rate of pressure rise' determination. The rate was typically 10-12 torr l. cm-2 sec-1 and about 99% or more of the gas was hydrogen. Since stainless steel usually contains large amounts of hydrogen and the diffusion coefficient of hydrogen in stainless steel is high, it was suspected that the hydrogen diffuses to the surface from the interior of the metal and is released into the vacuum. Calculations show that the observed outgassing rate could be explained by such a process and should be reduced by several orders of magnitude by a high-temperature treatment. The effects of residual hydrogen in the treatment furnace and hydrogen permeation from the atmosphere are also considered in these calculations. The greater the thickness of the metal, the higher the temperature has to be. Measurements are in reasonable agreement with these calculations.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"235 1","pages":"1459-1472"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79946629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/306
R. Enoch, Anne Winterborn
The first anisotropy constant at room temperature of a 77Ni-14Fe-5Cu -4Mo wt.% alloy has been measured; both its magnitude and its sign are shown to be dependent on the degree of short-range order in the alloy. The effect of the anisotropy on the magnetic properties of the alloy has been determined for various states of order. The highest initial permeability and the lowest coercivity occur for a vanishingly small anisotropy associated with a critical amount of order. Infinite permeability is prevented by the presence of a magnetoelastic anisotropy arising from internal stresses: the magnitude of this anisotropy can be determined.
{"title":"Magnetic characteristics of a high-permeability Ni-Fe-Cu-Mo alloy","authors":"R. Enoch, Anne Winterborn","doi":"10.1088/0508-3443/18/10/306","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/306","url":null,"abstract":"The first anisotropy constant at room temperature of a 77Ni-14Fe-5Cu -4Mo wt.% alloy has been measured; both its magnitude and its sign are shown to be dependent on the degree of short-range order in the alloy. The effect of the anisotropy on the magnetic properties of the alloy has been determined for various states of order. The highest initial permeability and the lowest coercivity occur for a vanishingly small anisotropy associated with a critical amount of order. Infinite permeability is prevented by the presence of a magnetoelastic anisotropy arising from internal stresses: the magnitude of this anisotropy can be determined.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"69 1","pages":"1407-1413"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76657346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/301
J. Filby, S. Nielsen
The preparation and properties of single-crystal films of silicon on insulating substrates are reviewed. Attempts have been made to prepare single-crystal films by epitaxial deposition on insulating substrates such as Al2O3, SiO2, MgAl2O4, SiC and BeO, and to a lesser extent by recrystallization and controlled-nucleation experiments on amorphous substrates. Evaporation, sublimation, sputtering, vapour-liquid-solid processes, and vapour techniques, including silane, silicon tetrachloride and other silicon halides, have been used to deposit silicon films. The differences between these processes and the factors affecting the perfection of films are discussed. A good deal of research has been devoted to silicon films on single-crystal sapphire substrates. Although diode, field-effect and bipolar devices have been fabricated the perfection of the films is still inadequate for some purposes. Factors affecting the perfection include interaction of the substrate and film during deposition, the perfection of the substrate surface, the nucleation and growth processes, and the presence of impurities and stresses in the film. Particular attention is paid to the orientation relationships between the silicon and the sapphire.
{"title":"Single-crystal films of silicon on insulators","authors":"J. Filby, S. Nielsen","doi":"10.1088/0508-3443/18/10/301","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/301","url":null,"abstract":"The preparation and properties of single-crystal films of silicon on insulating substrates are reviewed. Attempts have been made to prepare single-crystal films by epitaxial deposition on insulating substrates such as Al2O3, SiO2, MgAl2O4, SiC and BeO, and to a lesser extent by recrystallization and controlled-nucleation experiments on amorphous substrates. Evaporation, sublimation, sputtering, vapour-liquid-solid processes, and vapour techniques, including silane, silicon tetrachloride and other silicon halides, have been used to deposit silicon films. The differences between these processes and the factors affecting the perfection of films are discussed. A good deal of research has been devoted to silicon films on single-crystal sapphire substrates. Although diode, field-effect and bipolar devices have been fabricated the perfection of the films is still inadequate for some purposes. Factors affecting the perfection include interaction of the substrate and film during deposition, the perfection of the substrate surface, the nucleation and growth processes, and the presence of impurities and stresses in the film. Particular attention is paid to the orientation relationships between the silicon and the sapphire.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"7 1","pages":"1357-1496"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87042125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/302
R. Latham
Using single-crystal barium titanate with liquid electrodes, the pyroelectric effect has been used in a technique to extend the measurements of ferroelectric switching times to low fields. In the field range studied (0·2 ts > 10-4 sec) two significant transitions have been found in the switching behaviour at 0·54 kv cm-1 and 0·3 kv cm-1, appearing experimentally as discrete changes in the activation field. They have been shown to be due respectively to a modification in the nucleation mechanism of reversed domains and to the onset of charge compensation behind the moving domain walls.
{"title":"The low-field ferroelectric switching behaviour of barium titanate","authors":"R. Latham","doi":"10.1088/0508-3443/18/10/302","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/302","url":null,"abstract":"Using single-crystal barium titanate with liquid electrodes, the pyroelectric effect has been used in a technique to extend the measurements of ferroelectric switching times to low fields. In the field range studied (0·2 ts > 10-4 sec) two significant transitions have been found in the switching behaviour at 0·54 kv cm-1 and 0·3 kv cm-1, appearing experimentally as discrete changes in the activation field. They have been shown to be due respectively to a modification in the nucleation mechanism of reversed domains and to the onset of charge compensation behind the moving domain walls.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"94 1","pages":"1383-1388"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87506279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/314
P. Spencer, J. N. Pratt
The vapour pressure of manganese has been measured over the temperature range 1250-1550°K by means of the torsion-effusion technique. The data have been treated by the Third Law method and a value of the standard heat of sublimation (ΔH0298) of 68 095 ± 400 cal per gramme atom obtained (ΔH00 = 67 805 cal per gramme atom). Vapour pressure equations for the β, γ, δ and liquid forms of manganese have been computed.
{"title":"A study of the vapour pressure of manganese using a new high-temperature torsion - effusion apparatus","authors":"P. Spencer, J. N. Pratt","doi":"10.1088/0508-3443/18/10/314","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/314","url":null,"abstract":"The vapour pressure of manganese has been measured over the temperature range 1250-1550°K by means of the torsion-effusion technique. The data have been treated by the Third Law method and a value of the standard heat of sublimation (ΔH0298) of 68 095 ± 400 cal per gramme atom obtained (ΔH00 = 67 805 cal per gramme atom). Vapour pressure equations for the β, γ, δ and liquid forms of manganese have been computed.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"87 1","pages":"1473-1478"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90869221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/311
R. Khan
Cerenkov radiation in two semi-infinite dielectric media due to a point charge moving parallel to the plane interface has been calculated as a simple boundary-value problem. The results obtained differ from those of Danos, Linhart and Pafomov but are in complete agreement with the formulae for Cerenkov radiation in an infinite homogeneous dielectric medium and in a semi-infinite homogeneous dielectric medium with the plane conducting boundary as the limiting case. No discrepancy arises on interchanging dielectric constants if the particle moves along the common boundary plane. The result obtained from the radiation formula by a Linhart-type approximation is superior to Linhart's result from the point of view of rigour.
{"title":"Cerenkov radiation by a point charge moving parallel to the plane interface between two semi-infinite dielectric media","authors":"R. Khan","doi":"10.1088/0508-3443/18/10/311","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/311","url":null,"abstract":"Cerenkov radiation in two semi-infinite dielectric media due to a point charge moving parallel to the plane interface has been calculated as a simple boundary-value problem. The results obtained differ from those of Danos, Linhart and Pafomov but are in complete agreement with the formulae for Cerenkov radiation in an infinite homogeneous dielectric medium and in a semi-infinite homogeneous dielectric medium with the plane conducting boundary as the limiting case. No discrepancy arises on interchanging dielectric constants if the particle moves along the common boundary plane. The result obtained from the radiation formula by a Linhart-type approximation is superior to Linhart's result from the point of view of rigour.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"64 1","pages":"1443-1451"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81028984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/315
A. Jones, D. L. Misell
A general method is given for the correction of experimental spectra when they have been distorted according to the convolution integral described, where F(x) is the observed spectrum, f(x) is the true profile and S(x) is the slit function or intrinsic broadening function. The method is applied to the three main types of slit functions which are encountered in practice, namely the exponential, Gaussian and Cauchy distributions.
{"title":"A practical method for the deconvolution of experimental curves","authors":"A. Jones, D. L. Misell","doi":"10.1088/0508-3443/18/10/315","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/315","url":null,"abstract":"A general method is given for the correction of experimental spectra when they have been distorted according to the convolution integral described, where F(x) is the observed spectrum, f(x) is the true profile and S(x) is the slit function or intrinsic broadening function. The method is applied to the three main types of slit functions which are encountered in practice, namely the exponential, Gaussian and Cauchy distributions.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"19 1","pages":"1479-1483"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86866692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/305
G. Ranzetta, V. Scott
Microanalysis measurements have been carried out on a series of copper-nickel alloys. An atomic-number effect which could lead to errors exceeding 5% in quantitative work was found to be present in this system, a result which substantiates theoretical predictions.
{"title":"The effect of atomic number in electron-probe microanalysis of copper-nickel alloys","authors":"G. Ranzetta, V. Scott","doi":"10.1088/0508-3443/18/10/305","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/305","url":null,"abstract":"Microanalysis measurements have been carried out on a series of copper-nickel alloys. An atomic-number effect which could lead to errors exceeding 5% in quantitative work was found to be present in this system, a result which substantiates theoretical predictions.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"36 1","pages":"1403-1406"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87217381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1967-10-01DOI: 10.1088/0508-3443/18/10/307
M. Darby
The Brillouin function and the spontaneous magnetization derived from it are tabulated for spin values ½ to 7/2 in half-integral steps and for J = ∞.
在自旋值为1 /2至7/2的半积分步长和J =∞时，布里因函数和由它推导出的自发磁化率表。
{"title":"Tables of the Brillouin function and of the related function for the spontaneous magnetization","authors":"M. Darby","doi":"10.1088/0508-3443/18/10/307","DOIUrl":"https://doi.org/10.1088/0508-3443/18/10/307","url":null,"abstract":"The Brillouin function and the spontaneous magnetization derived from it are tabulated for spin values ½ to 7/2 in half-integral steps and for J = ∞.","PeriodicalId":9350,"journal":{"name":"British Journal of Applied Physics","volume":"6 1","pages":"1415-1417"},"PeriodicalIF":0.0,"publicationDate":"1967-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86110441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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