Hall Effect Devices for Low Level Magnetic Detection

N. P. MILLIGAN and J. P. BURGESS Ohio Semiconductors

Columbus, Ohio

detection devices combining optimized Gall plates and magnetic concentrators. The paper covers the design and erformance of improved low magnetic

The factors relating to the fabrication of a high gain concentrator are presented, and a Hall effect device com atible with this magnetic structure is then developed. Wide band width, s t ab l operation, shock and vibration, out, put voltage, power requirements, all relative to low level performance are considered.

Performance data from several devices is presented and operational char, acteristics discussed. The relationships of concentrator length and air gap or

that of the ambient magnetic field. fndium Arsenide, fndium Antimonide and Hall plate thickness are utilized to rovide magnetic ains of over 100 times

other 111-IV compound semiconductor devices are shown to be ideally suited for this application due to the combination of high mobility, low raise tivity, high purity and tem erature characteristics. Exceptional erformance is achieved in one sensor Besigned for operation at -196' C. %us sensor exhibits an overall sensitivity of 2500 volts per ampere kilogauss as well as exceptional stability.

In conclusion, the feasability of further improvement in sensitivity, weight reduction, size and power requirements is discussed.

Hall-Effect Vector-Product Generators

W. SARAGA and R. K. P. GALPIN A. E . I. Limited

London, England

of the Hall effect, the devices to be discussed here are genuine vectoreproduct Whereas conventional Hall multipliers make no use of the uectovial aspect

generators, able to accept vectorial input signals and to produce an output

vectors. In particular, devices will be considered which generate either an OUP signal in the direction of, and proportional to, the vector product of the input

vector from one rotating and one fixedpdirection in ut vector (the rotations put vector of fixed direction from two rotating input vectors or a rotating

occurring at constant angular frequencies). In the &st case an output signal containing either the sum or the difference of the input frequencies is obtained.

plane but in different directions can be extracted. Possible applications of such In the second case separate vectorial output components rotating in the same

devices to telecommunication problems will be indicated.

element (instead of a conventional thin plate), with low efficiency, and with The validity of the new principle was confirmed with a cubesshaped Hall,

a cruciform element, with improved efficiency (a thin, late version, possessing the efficiency of conventional Hall multipliers will arm be discussed). The choice of semiconductor material and the construction of the new devices will be treated in some detail.

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