Source Publication (e.g., journal title)
Physical Review B
We combine optical and magneto-optical spectroscopies with complementary vibrational and magnetic property measurements to reveal finite length scale effects in nanoscale α-Fe2O3. Analysis of the d-to-d on-site excitations uncovers enhanced color contrast at particle sizes below approximately 75 nm due to size-induced changes in spin-charge coupling that are suppressed again below the superparamagnetic limit. These findings provide a general strategy for amplifying magnetochromism in α-Fe2O3 and other iron-containing nanomaterials that may be useful for advanced sensing applications.We also unravel the size dependence of collective excitations in this iconic antiferromagnet.
O'Neal, Kenneth Robert; Patete, J M.; Chen, P; Nanavati, R; Holinsworth, Brian S.; Smith, J M.; Marques, C; Simonson, J W.; Aronson, M C.; McGill, Stephen A.; Wong, S S.; and Musfeldt, Janice L., "Magnetochromic sensing and size-dependent collective excitations in iron oxide nanoparticles" (2017). Chemistry Publications and Other Works.