摘要:

Single crystals of magnetic garnets have been grown from solutions of molten lead oxied, iron oxide, and the oxides of yttrium, samarium, erbium, or gadolinium. The crystals are grown by slowly cooling melts from 1325°C to near 900°C. A convenient composition is 52.5 mole % PbO, 44 mole % Fe2O3, and 3.5 mole % M2O3whereMis Y, Gd, Er, or Sm. Crystals of yttrium‐iron garnet have been grown which contain gallium partially substituted for iron.The method may also be extended to the growth of nonmagnetic yttrium gallium garnets by using a melt which is 72.7 mole % PbO, 26 mole % Ga2O3and 1.3 mole % Y2O3.Bismuth oxide can be used as a solvent for the growth of magnetic garnet crystals but the substitution of bismuth in the garnet lattice makes it less desirable than lead oxide.

ISSN:0021-8979    

DOI:10.1063/1.1723148

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The antiferromagnetic structures of MnS2, MnSe2, and MnTe2have been obtained by neutron diffraction. The disulfide exhibits ordering of the ``third'' kind, the ditelluride, ordering of the ``first'' kind, and the diselenide, an arrangement which is intermediate between the two. The structures are discussed from the viewpoint of indirect exchange.

ISSN:0021-8979    

DOI:10.1063/1.1723149

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

Methods for measuring ferrites at high inductions are given. For frequencies below 50 Mc, a conventional series resonant circuit is used, and coupled to a high power signal source through a variable capacitive attenuator. The test sample is in the form of a toroid with an appropriate winding. TheQof the test sample is determined with the aid of an air coil whoseQis known. Harmonics, sources of errors, and pulse modulation are discussed. For frequencies of 50 Mc and above, a short circuited coaxial slotted line is used. To get high currents into the slotted line, it is inductively coupled to a high power signal source and tuned to resonance by means of a capacitor. A method for determining the current in the line is given.

ISSN:0021-8979    

DOI:10.1063/1.1723150

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

An investigation was conducted directed toward securing data for choosing the best ferrite to be used in the Penn‐Princeton 3 Bev high intensity proton synchrotron now being built at Princeton University. The ferrite samples tested were from American and European manufacturers and were in the form of small rings 2 inches or less in diameter. Measurements were required of &mgr; andQunder varying magnetic bias, at variousrfflux levels, in the band frequencies 2.5 to 45 megacycles per second. At the beginning of this research no clear method existed for a proper choice of ferrite, and generally speaking the manufacturers' data were inadequate. Therefore a novel technique of measurement was devised, and an effort was made to establish a minimum number of parameters for defining ferrite properties for this application. The present paper includes a description of the techniques used and a resume of the results obtained.

ISSN:0021-8979    

DOI:10.1063/1.1723151

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A computation is described which reveals the exact values of the propagation constants of theTEmodes in rectangular wave guide loaded with a transversely magnetized ferrite slab over a frequency interval which includes resonance. Magnetic losses are included in the analysis. It is shown that the way in which the modes link through resonance depends upon the value of the magnetic damping parameter, and further that they generally link in such a way that an interference between two or more modes will occur.

ISSN:0021-8979    

DOI:10.1063/1.1723152

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The theory of wave propagation in circular wave guides containing coaxial longitudinally‐magnetized ferrite rods is examined for cases where the rod diameter is too large for accurate perturbation treatment. Several solutions of the transcendental equation have been computed with the aid of experimental data. Field distribution and energy concentration data thus obtained are given for several cases for positive and negative rotating waves.

ISSN:0021-8979    

DOI:10.1063/1.1723153

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The radiation resistance and reactance of point source dipoles are profoundly affected by the surrounding medium. A radiator of lengthlin an infinite ferrite medium is electrically &mgr;lmeters long if &mgr;=&egr; (relative permeability and permittivity).For very small ferrite spheres, the radiation resistance is determined by the relative permittivity, the effective reactance length by both the permittivity and the permeability. Thus it is possible to exchange length for resistance. Further work on linear radiators surrounded by ferrite in the form of a prolate figure of revolution is indicated.

ISSN:0021-8979    

DOI:10.1063/1.1723154

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

In the magnetic focusing of electron beams there is a growing need for permanent magnets of higher coercive force than those which are easily obtainable. Special techniques in the design of compact tubular magnets for strong focusing fields enable the use of magnet materials of relatively low remanence. The low remanence of some materials suitable for this use has limited their general use and this has probably retarded their final development. There is a good potential demand for these materials for electron beam focusing which should stimulate increased development effort.

ISSN:0021-8979    

DOI:10.1063/1.1723155

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The objective of this investigation was to determine the effect of temperature up to 600°C and vibration on the performance of Alnico V and Alnico VI magnets. Data is presented on the effect of cycling stability, coefficient of remanence, extended exposure to elevated temperature and vibration.The results of this investigation show that the use of Alnico V and Alnico VI in most instrument and control applications is feasible up to 500°C. However, a considerable loss in properties should be expected if the temperature exceeds 500°C.

ISSN:0021-8979    

DOI:10.1063/1.1723156

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A measurement system was developed to measure variations in the flux density normal to the pole faces of short axially‐magnetized cylindrical permanent magnets. A quartz crystal vibrated a single‐turn pickup coil to scan an area 0.028 in.×0.00002 in. at a distance of 0.010 in. from the pole face. Circumferential variation of flux density was used as the uniformity criterion. For magnets compacted from powders variations may be held to less than 4% of the average. Directional materials such as cast Alnico V show variations as high as 17%.

ISSN:0021-8979    

DOI:10.1063/1.1723157

出版商:AIP    

年代:1958

数据来源: AIP