%0 Journal Article
%A Hoppe, Michael
%A Döring, Sven
%A Gorgoi, Mihaela
%A Cramm, Stefan
%A Müller, Martina
%T Enhanced ferrimagnetism in auxetic NiFe$_{2}$O$_{4}$ in the crossover to the ultrathin-film limit
%J Physical review / B
%V 91
%N 5
%@ 1098-0121
%C College Park, Md.
%I APS
%M FZJ-2015-05431
%P 054418
%D 2015
%X We investigate the sensitive interplay between magnetic, electronic, and structural properties in the ferrimagnetic oxide NiFe2O4. Emphasis is placed on the impact of reduced dimensionality in the crossover from bulk-like to ultrathin films. We observed an enhanced saturation magnetization MS for ultrathin NiFe2O4 films on Nb-SrTiO3 (001) substrates that co-occurs with a reduced out-of-plane lattice constant under compressive in-plane epitaxial strain. We found a bulk-like cationic coordination of the inverse spinel lattice independent of the NiFe2O4 film thickness, thus ruling out a cationic inversion that nominally could account for an enhanced MS. Moreover, our study instead uncovers a reduction of the unit cell volume, i.e., an auxetic behavior in ultrathin NiFe2O4 films.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000350102600001
%R 10.1103/PhysRevB.91.054418
%U https://juser.fz-juelich.de/record/203511