TUNNELING MAGNETO-RESISTANCE EFFECT AND GIANT HALL EFFECT IN Fe-SiO₂ GRANULAR FILMS

Fe-SiO₂ metal-insulator granular films with various metal volume fractions（f_v） were fabricated by RF co-sputtering.The microstructure and tunneling magneto-resistance（TMR） as well as the giant Hall effect（GHE） were systematically investigated.The Fe_0.33（SiO₂）_0.67 film exhibits the largest TMR value of-3.3% at room temperature under 1.3 T magnetic field.The sample with f_v=0.52 exhibits the largest Hall resistivity of 18.5 μΩ·cm.The Hall resistivity does not decrease much,when the Fe_0.52（SiO₂）_0.48 granular film annealed at different temperature up to 300 ℃.It indicates a good thermal stability of GHE for this film.Thus the film may be considered as a magnetic field sensor for operating temperature below 300 ℃.