Abstract: A unique dual track recording technique is described in which complementarily magnetically poled regions are simultaneously written in adjacent positions in two parallel tracks. Multi-track recording of magnetic data transitions in oppositely poled matched zones in the separate tracks provides a high flux coupling to a magnetic sensor. The sensor is exposed to the combined flux from both tracks. This also provides a high degree of data redundancy in the event of small physical anomalies in the magnetic medium or writing anomalies in one track or the other. Because a large magnetic field may be coupled, a magnetic sensor may be positioned at some substantial distance above the magnetic medium on which the data is recorded. This overcomes a significant problem in data reading and writing. The present limits of proximity to the magnetic medium of the sensor head or write head have been reached and still higher data density is desired.

Abstract: A new semiconductive device for sensing uniaxial magnetic fields is described. The sensor is essentially a dual collector lateral bipolar transistor operated in the avalanche region. Each of the collectors exhibits two space charge resistance effects. One effect produces a negative resistance and the other produces a positive resistance. When the two space charge resistances are carefully balanced, a net zero collector resistance is achieved. A balanced condition can be maintained for a broad range of collector currents. A vertical VI property is thereby achieved. It has been found that the positive space charge resistance characteristic is inversely proportional to the ionization area and that the negative component is proportional to the area in the avalanche zone at each collector. It has been found that a magnetic field can modulate the ionization areas at the collector junctions.

Abstract: A heretofore undiscovered suddenly conducting avalanche voltage effect is described with relationship to a new family of hybrid transistors. The devices constructed also exhibit magnetic sensitivity. The magnetic responsiveness of such devices creates a new family of magnetic sensors which utilize magnetic modulation of the avalanche voltage produced by the new effect. New transistor structure elements are incorporated in the devices. These include an impact ionization promoter means and an intrinsic, or high resistivity, depleted base region which extends at least partially from a collector toward an emitter. Minority carrier injection efficiency control means and transportation efficiency control means are also included. The character of the base region extending between the emissive junction and the collector is carefully controlled so that the product of the ionization current multiplication factor M and an electron-hole recombination probability factor .alpha. is less than unity.

Abstract: A high sensitivity, low noise, broad bandwidth, twin channel conduction Lorentz channel coupled semiconductive field sensor device is described. The conductive channels are configured to create exceptionally narrow, undepleted conduction zones of approximately filamentary form. The filamentary conductive channels so formed are provided with a common source at one end of each channel and a separate drain at the other end thereof. The independent drains are spaced apart by a narrow area of semiconductive material. Magnetic fields may be utilized to create a Lorentz voltage in a region between the two conductive channels to vary the amount of current received at the two drains by utilizing the depletion width modulation effects of the Lorentz voltage upon the boundaries defining the conductive channel portions. Modulation of the depletion zone widths and depths along the channel sides effectively move the streams of carriers and the conductive channel areas to conduct more current to one drain more than another.

Abstract: A high sensitivity, low noise, broad bandwidth channel conduction field sensor device is described. The conductive channel is configured to create an exceptionally narrow, undepleted conduction channel of approximately filamentary form. The filamentary conductive channel so formed is provided with a source at one end of the channel and two or more laterally spaced drains at the other end thereof. Electric or magnetic fields may be utilized to deflect a stream of charge carriers traversing the conductive channel from the source toward the drains utilizing the depletion width modulation effect of the fields upon the boundaries defining the conductive channel portion. Modulation of the depletion zone width and depth along the channel sides effectively moves the stream of carriers and the conductive channel area to overlap one drain more than another. This develops a differential drain current balance which can be utilized to provide an output signal.