Scaling of Hall coefficient in Co-Bi granular thin films

¹ School of Engineering, University of Patras, 26504 Rion Patras, Greece
² Institute of Materials Science, NCSR Demokritos, 15310 Aghia Paraskevi, Athens, Greece

Abstract

A series of Co-Bi thin films with Co concentrations c=0, 0.05, 0.2, 0.26, 0.3, 0.333, 0.375, 0.545, were grown by magnetron sputtering on Si(100)/SiN_X substrates. Resistivity measurements at zero field (ρ_xx) as a function of temperature-T exhibit an exponential variation with T in the region of 240K<T<300K. The Hall coefficient as a function of Co concentration diverges as log|c-0.3|^0.3 for c<0.333, indicating a scaling of R_H nearby a percolation threshold p_c=0.3. Only after proper scaling of the anomalous Hall coefficient R_S the conventional R_S∝(ρ_xx)ⁿ dependence can be satisfied.