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IBM Journal of Research and Development

Issue 4 • Date Oct. 1962

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Displaying Results 1 - 16 of 16
  • Static Reversal Processes in Thin Ni-Fe Films

    Publication Year: 1962 , Page(s): 394 - 406
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1152 KB)  

    Magnetization reversal at an angle to the easy direction in Ni-Fe films was studied. The results, in contrast to the single-domain theory, show no coherent rotation, even for field directions in which the critical field for rotation is smaller than the critical field for wall motion. The actual reversal is initiated by rotation of the magnetization in bands formed in the film. New experimental studies show that the reversal is subsequently completed by wall motion. A qualitative discussion of the new observations and a review of previous work give a comprehensive picture of the static reversal processes in thin Ni-Fe films. View full abstract»

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  • A Discrete Queueing Problem with Variable Service Times

    Publication Year: 1962 , Page(s): 407 - 418
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (887 KB)  

    Methods from the theory of Markov chains are used to analyze a simple single-server queueing model. The model is of the sort that arises naturally in information-handling contexts, in that a discrete time basis is used, which matches the cyclic character of processors. Considerable generality is attained, in that no appeal is made to the exponential or other conventional forms for the probability distributions governing the number of arrivals per cycle and the service times. The principal object of study is the queue length; the stationary distribution governing this quantity is calculated, along with various associated averages. The relation between the present method and the more usual continuous-variable method is illustrated by the derivation of some of the classical equations from a limiting case of our model. View full abstract»

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  • Analysis of Static and Quasidynamic Behavior of Magnetostatically Coupled Thin Magnetic Films

    Publication Year: 1962 , Page(s): 419 - 429
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    When two superposed films exert fields on each other, their static and dynamic behaviors change. The following method or analysis is used to study the behavior: The stable states are found by minimizing the total free energy of the films. Then constant-field contours are plotted in the θ1–θ2 plane (θ's being the stable orientations of the magnetization vectors). In examining the plot, one can predict multiple stable states, switching, threshold, hysteresis, and the detailed paths of magnetization change as a function of applied field. The solution is carried out by a numerical process which permits evaluation of the following effects: the variation of the degrees of symmetries of the anisotropy energies, the relative orientation between the films, the coupling strength, and the drive-line layout. An example is carried out in sufficient detail for illustrative purposes. View full abstract»

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  • Coding for Logical Operations

    Publication Year: 1962 , Page(s): 430 - 436
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (685 KB)  

    The behavior of a computation system consisting of encoders, an unreliable logical operator and a decoder is investigated. It is shown that for almost all Boolean functions, coding each block of k input bits into a block of n bits such that all sets of s or less errors will be corrected requires that n ≥ (2s + 1)k. This result suggests that the capacity (in the information theoretical sense) of such a computation system is zero. View full abstract»

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  • Experimental Study of Electron-Beam Driven Semiconductor Devices for Use in a Digital Memory

    Publication Year: 1962 , Page(s): 437 - 448
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1037 KB)  

    A novel method of electronic storage is proposed, in which an electron beam would be used to drive active and passive semiconductor devices to perform the functions of a digital memory, including those of nondestructive read-out and reset. Principally to ascertain what speeds and output signals might be currently obtained if the storage method were implemented, an experimental study was made of the response to a bombarding electron beam of commercial “four-layer” and surface-barrier diodes which could function in the proposed store respectively as storage diodes and read-out diodes. Data presented on the Shockley Laboratories’ silicon 4N20D “four-layer” diode give the reduction of firing voltage caused by the bombardment as a function of beam current and bombardment duration. It is found that a beam current as weak as 0.2 µamp can fire a diode in 1/5 µsec. Three types of germanium surface-barrier diodes were studied for maximum speed of response to the bombarding beam current pulse and for charge multiplication. The “fastest” unit tested was a Philco 2N502 transistor modified for beam access to the base region by removal of the emitter dot. This unit could be bombarded to produce a 50 nsec pulse of 0.4 v peak across a 1000-ohm load. In the light of these data and of circuit and semiconductor device theory, a preliminary discussion is presented of the feasibility of a store providing a read-in rate of 5 megapulses/sec, a read-out rate of 15 megapulses/sec and a read-out signal ratio of stored ones to stored zeroes of 50 to 1. View full abstract»

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  • Residual Stress in Single-Crystal Nickel Films

    Publication Year: 1962 , Page(s): 449 - 455
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (728 KB)  

    Experiments are described which directly indicate the source, magnitude and direction of the residual stress on single-crystal nickel films evaporated on rock salt. A theoretical analysis using the five-constant magnetostriction equation shows how this stress affects the magnetic properties. X-ray diffraction studies indicate that the as-evaporated films exist in a highly strained condition, resulting in a tetragonal distortion of the cubic symmetry. The parameters of the unit cell are a = b = 3.500 ± 0.004 A in the plane of the film and c = 3.546 ± 0.002 A normal to the film. The stress causing this strain is elastic in character. When the film is floated off the rock salt, the parameter decreases to bulk unstrained Ni, a0 = 3.524 A. The calculation using bulk elasticity data yields a planar compressive stress σ = 1.0 × 1010 dyne/cm2, from differential thermal expansion between nickel film and NaCl substrate. This externally applied stress system influences the magnetic state of the film by contributing to the total energy of the system through a magnetoelastic interaction. View full abstract»

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  • A Polarimetric Method of Measuring Magneto-Optic Coefficients

    Publication Year: 1962 , Page(s): 456 - 461
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (516 KB)  

    Formulas are established which allow polarimetric determination of the amplitudes and relative phases of the Kerr (and Faraday) coefficients for ferromagnetic metals. The results are valid only for oblique angles of incidence. Hence, the technique is most useful for measurement of thin films where the magnetization vector lies in the plane of the film. View full abstract»

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  • Printed Cards for the Card Capacitor Memory [Letter to the Editor]

    Publication Year: 1962 , Page(s): 462 - 463
    Save to Project icon | PDF file iconPDF (303 KB)  
    Freely Available from IEEE
  • Determination of Lattice Strain and Crystallite Size in Thin Films [Letter to the Editor]

    Publication Year: 1962 , Page(s): 464 - 466
    Save to Project icon | PDF file iconPDF (406 KB)  
    Freely Available from IEEE
  • Direct Observations of the Substructure Network in Iron [Letter to the Editor]

    Publication Year: 1962 , Page(s): 467 - 469
    Save to Project icon | PDF file iconPDF (495 KB)  
    Freely Available from IEEE
  • A Note on Some Fundamental Parameters of Multiqueue Systems [Letter to the Editor]

    Publication Year: 1962 , Page(s): 470 - 471
    Cited by:  Papers (2)
    Save to Project icon | PDF file iconPDF (304 KB)  
    Freely Available from IEEE
  • Effect of Initial Air Content on the Dynamics of Bubbles in Liquids [Letter to the Editor]

    Publication Year: 1962 , Page(s): 472 - 474
    Save to Project icon | PDF file iconPDF (370 KB)  
    Freely Available from IEEE
  • IBM Technical Papers Published Recently in Other Journals

    Publication Year: 1962 , Page(s): 475 - 486
    Save to Project icon | PDF file iconPDF (747 KB)  
    Freely Available from IEEE
  • Recent IBM Patents

    Publication Year: 1962 , Page(s): 487 - 489
    Save to Project icon | PDF file iconPDF (239 KB)  
    Freely Available from IEEE
  • Authors

    Publication Year: 1962 , Page(s): 490 - 491
    Save to Project icon | PDF file iconPDF (212 KB)  
    Freely Available from IEEE
  • Contents of previous three issues

    Publication Year: 1962 , Page(s): 492
    Save to Project icon | PDF file iconPDF (235 KB)  
    Freely Available from IEEE

Aims & Scope

The IBM Journal of Research and Development is a peer-reviewed technical journal, published bimonthly, which features the work of authors in the science, technology and engineering of information systems.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Clifford A. Pickover
IBM T. J. Watson Research Center