Spin canting in ferrite nanoparticles

Recently, an easily scalable process for the production of small (3-7 nm) monodisperse superparamagnetic ferrite nanoparticles MeFe2O4 (Me = Zn, Mn, Co) from iron metal and octanoic acid has been reported (Salih et al., Chem. Mater. 25 1430-1435 2013). Here we present a Mossbauer spectroscopic study of these ferrite nanoparticles in external magnetic fields of up to B = 5 T at liquid helium temperatures. Our analysis shows that all three systems show a comparable inversion degree and the cationic distribution for the tetrahedral A and the octahedral B sites has been determined to (Zn0.19Fe0.81)(A)[Zn0.81Fe1.19]O-B(4), (Mn0.15Fe0.85)(A)[Mn0.85Fe1.15]O-B(4) and (Co0.27Fe0.73)(A)[Co0.73Fe1.27]O-B(4). Spin canting occurs presumably in the B-sites and spin canting angles of 33 degrees, 51 degrees and 59 degrees have been determined for the zinc, the manganese, and the cobalt ferrite nanoparticles.