TY  - JOUR
AU  - Hoppe, Michael
AU  - Döring, Sven
AU  - Gorgoi, Mihaela
AU  - Cramm, Stefan
AU  - Müller, Martina
TI  - Enhanced ferrimagnetism in auxetic NiFe$_{2}$O$_{4}$ in the crossover to the ultrathin-film limit
JO  - Physical review / B
VL  - 91
IS  - 5
SN  - 1098-0121
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2015-05431
SP  - 054418
PY  - 2015
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000350102600001
DO  - DOI:10.1103/PhysRevB.91.054418
UR  - https://juser.fz-juelich.de/record/203511
ER  -