Sign of the superexchange coupling between next-nearest neighbors in EuO

Abstract

The sign of the superexchange coupling J 2 between next nearest neighboring Eu 2+ magnetic moments in EuO is a matter subject to debate. We have obtained evidence

Magnetoelectric coupling at the EuO/BaTiO3 interface

“…Prior studies reported an increase in Curie temperature for EuO with electron doping (n-type doping of the EuO). 12,29 As seen in Figure 2, there is no significant change in the critical magnetization temperature neither for LSMO (Ref. 23) nor for EuO with polarization reversal in BTO.…”

“…The magnetic properties were measured with a physical properties measurement system (PPMS) from Quantum Design. 12,15,29 As seen in Figure 1, the 100-nm-thick EuO films are textured along (100). The results obtained for the EuO/BaTiO 3 samples are here compared with the data obtained previously using epitaxial BaTiO 3 films on La 0.67 Sr 0.33 MnO 3 /SrTiO 3 (LSMO/STO) substrates.…”

“…16 Metal-toinsulator transition and colossal magneto-resistance have been reported in EuO systems with electron doping. 14,[17][18][19][20] Much effort has been put into investigating the influence of the substrate on the magnetic properties of EuO [2][3][4][5][6]11,12,21,22 including changes to the Curie temperature (T c ) and critical exponents. Ferroelectric (FE) substrates are unique due to the potential for electric modulation, coming from the ferroelectric polarization reversal, which can be considered as a form of extrinsic electrostatic doping at the FM-FE interfaces.…”

“…In particular, EuO has an accessible Curie temperature 7 (T c ) of 69 K that is seen to be sensitive to lattice strain. [8][9][10][11][12] The EuO system contains localized magnetic moments of 4f moments [13][14][15] and in the ferromagnetic state exhibits very large magneto-optical effects. 16 Metal-toinsulator transition and colossal magneto-resistance have been reported in EuO systems with electron doping.…”

Real-space Green's function approach to angle-resolved resonant photoemission: Spin polarization and circular dichroism in itinerant magnets

“…The element and orbital selectivity of core level resonant spectroscopies allows to access higher order multipoles which are left unexplored by MCD in X-ray absorption (XAS) [1][2][3][4][5][6], to distinguish and enhance specific electronic excitations and satellites [7,8], collective magnetic excitations [9], ultrafast and charge transfer dynamics [10][11][12] and to detect quadrupolar transitions towards localized empty states [13,14]. In particular, RPES has recently been applied to several correlated materials [15][16][17][18][19] and full two dimensional angular scans of resonantly emitted electrons in moderately correlated materials have also been carried out [20,21]. These works, together with earlier pioneering studies [22,23] on local magnetic properties in macroscopically non magnetic systems, demonstrate the importance of RPES and the need for an advancement in the theoretical description of this spectroscopy, which is the main aim of this work.…”