TY  - JOUR
A1  - Hsu, Pin-Jui
A1  - Kügel, Jens
A1  - Kemmer, Jeannette
A1  - Toldin, Francesco Parisen
A1  - Mauerer, Tobias
A1  - Vogt, Matthias
A1  - Assaad, Fakher
A1  - Bode, Matthias
T1  - Coexistence of charge and ferromagnetic order in fcc Fe
JF  - Nature Communications
N2  - Phase coexistence phenomena have been intensively studied in strongly correlated materials where several ordered states simultaneously occur or compete. Material properties critically depend on external parameters and boundary conditions, where tiny changes result in qualitatively different ground states. However, up to date, phase coexistence phenomena have exclusively been reported for complex compounds composed of multiple elements. Here we show that charge- and magnetically ordered states coexist in double-layer Fe/Rh(001). Scanning tunnelling microscopy and spectroscopy measurements reveal periodic charge-order stripes below a temperature of 130 K. Close to liquid helium temperature, they are superimposed by ferromagnetic domains as observed by spin-polarized scanning tunnelling microscopy. Temperature-dependent measurements reveal a pronounced cross-talk between charge and spin order at the ferromagnetic ordering temperature about 70 K, which is successfully modelled within an effective Ginzburg–Landau ansatz including sixth-order terms. Our results show that subtle balance between structural modifications can lead to competing ordering phenomena.
KW  - ferromagnetism
KW  - phase transitions and critical phenomena
KW  - coexistence
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173969
VL  - 7
ER  - 
TY  - JOUR
A1  - Hausoel, A.
A1  - Karolak, M.
A1  - Şaşιoğlu, E.
A1  - Lichtenstein, A.
A1  - Held, K.
A1  - Katanin, A.
A1  - Toschi, A.
A1  - Sangiovanni, G.
T1  - Local magnetic moments in iron and nickel at ambient and Earth's core conditions
JF  - Nature Communications
N2  - Some Bravais lattices have a particular geometry that can slow down the motion of Bloch electrons by pre-localization due to the band-structure properties. Another known source of electronic localization in solids is the Coulomb repulsion in partially filled d or f orbitals, which leads to the formation of local magnetic moments. The combination of these two effects is usually considered of little relevance to strongly correlated materials. Here we show that it represents, instead, the underlying physical mechanism in two of the most important ferromagnets: nickel and iron. In nickel, the van Hove singularity has an unexpected impact on the magnetism. As a result, the electron–electron scattering rate is linear in temperature, in violation of the conventional Landau theory of metals. This is true even at Earth’s core pressures, at which iron is instead a good Fermi liquid. The importance of nickel in models of geomagnetism may have therefore to be reconsidered.
KW  - ferromagnetism
KW  - electronic properties and materials
KW  - magnetic properties and materials
KW  - nickel
KW  - iron
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170681
VL  - 8
IS  - 16062
ER  -