CONTACT PLACEMENT ERRORS FOR RESISTIVE AND HALL MEASUREMENTS ON CROSS-SHAPED SAMPLES

The calculation of lead-placement errors for resistivity and Hall signals is extended to the family of cross-shaped samples. Empirical expressions for errors [Δρ/ρ=- 1/2 (2d/D)2n and ΔR H/RH=- 1/2 (2d/D)n] are given in the limit of large contact displacement (d/D→ 1/2). For crosses, the exponent n was found to increase as n ∝ (l/D)-1.42 as the ratio of leg width to overall size, l/D, was reduced. For square and circular cloverleafs, n is less sensitive to the increase of the slit length, giving power laws with exponents of 0.8 and 0.6, respectively, in terms of the parameter λ=2r/D.