TY  - JOUR
AU  - Niklowitz, P. G.
AU  - Hirschberger, M.
AU  - Lucas, M.
AU  - Cermak, P.
AU  - Schneidewind, A.
AU  - Faulhaber, E.
AU  - Mignot, J.-M.
AU  - Duncan, W. J.
AU  - Neubauer, A.
AU  - Pfleiderer, C.
AU  - Grosche, F. M.
TI  - Ultrasmall Moment Incommensurate Spin Density Wave Order Masking a Ferromagnetic Quantum Critical Point in NbFe 2
JO  - Physical review letters
VL  - 123
IS  - 24
SN  - 1079-7114
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2020-01344
SP  - 247203
PY  - 2019
AB  - In the metallic magnet Nb1−yFe2þy, the low temperature threshold of ferromagnetism can be investigatedby varying the Fe excessywithin a narrow homogeneity range. We use elastic neutron scattering to trackthe evolution of magnetic order from Fe-rich, ferromagnetic Nb0.981Fe2.019to approximately stoichiometricNbFe2, in which we can, for the first time, characterize a long-wavelength spin density wave state burying aferromagnetic quantum critical point. The associated ordering wave vectorqSDW¼ð0;0;lSDWÞis found todepend significantly onyandT, staying finite but decreasing as the ferromagnetic state is approached. Thephase diagram follows a two-order-parameter Landau theory, for which all of the coefficients can now bedetermined. Our findings suggest that the emergence of spin density wave order cannot be attributed toband structure effects alone. They indicate a common microscopic origin of both types of magnetic orderand provide strong constraints on related theoretical scenarios based on, e.g., quantum order by disorder.
LB  - PUB:(DE-HGF)16
C6  - pmid:31922868
UR  - <Go to ISI:>//WOS:000502130400008
DO  - DOI:10.1103/PhysRevLett.123.247203
UR  - https://juser.fz-juelich.de/record/874253
ER  -