Approaching the pT range with a 2DEG InGaAs/InP Hall sensor at 77 K

The noise of two-dimensional electron gas InGaAs/InP Hall sensors of variou s dimensions was studied. In the first part of the work we show that for la rge-scale sensors ( > 0.2 mm linear dimension) at 77 K and at 1 kHz, a sens itivity better then 1 nT can be achieved. The second part of present work d eals with the noise measurements of 2 and 10 mu m sensors dependent on bias current, frequency, applied magnetic field and temperature. It was found t hat the low-frequency noise of the 10 mu m sensor rapidly increased for app lied magnetic field, but the noise of the 2 mu m sensor is a complicated fu nction of temperature and magnetic field, for low temperatures and fields 1 -3 T is the low-frequency noise of the sensor suppressed. (C) 2000 Elsevier Science B.V. All rights reserved.