New insights into defects and magnetic interactions inducing lattice disordering in Co₂Fe_0.5Cr_0.5Al

Abstract

This study shows the important role of the magnetic interactions between Fe, Co and Cr atoms in Co2Fe0.5Cr0.5Al elucidating for the first time the striking correlation of the effective value of the hyperfine field with the degree of ordering/disordering of the lattice.

Lattice Oxygen Activation Triggered by Ultrasonic Shock Significantly Improves NO Selective Catalytic Reduction

“…The six-line component with a magnetic splitting of about 53 T was present with a relative area of 94–95%, which corresponded to a magnetic hyperfine field close to the value for bulk α-Fe 2 O 3 at 10 K. The isomer shift (IS = 0.33 mm/s) and quadrupole splitting (QS = 0.39 mm/s) were also shown to be in accordance with the values for bulk α-Fe 2 O 3 at 10 K. In addition, the doublet component with isomer shift of 0.13 mm/s and quadrupole splitting of 2.5 mm/s was present with a relative area of 5–6% to the total spectral area. This component was reported to be related to the surface superparamagnetic Fe 3+ or grain boundary Fe 3+ atoms. , It was noted that UT-Fe 2 O 3 presented a smaller hyperfine field ( B hf ) (52.83 vs 53.26 T) than P-Fe 2 O 3 , indicative of an enhanced lattice disordering . The smaller magnetic field actually implied more disorders in the magnetic moment arrangement.…”

“…29,30 It was noted that UT-Fe 2 O 3 presented a smaller hyperfine field (B hf ) (52.83 vs 53.26 T) than P-Fe 2 O 3 , indicative of an enhanced lattice disordering. 31 The smaller magnetic field actually implied more disorders in the magnetic moment arrangement. These results collectively prove that ultrasonic treatment induced a change in the bulk structure of hematite via defect formation.…”