Magnetic structure of La0.7Sr0.3MnO3/La0.7Sr0.3FeO3 superlattices

Abstract

Using x-ray magnetic dichroism we characterize the magnetic order in La 0.7 Sr 0.3 MnO 3 (LSMO) / La 0.7 Sr 0.3 FeO 3 (LSFO) superlattices with 6 unit cell thick sublayers. The LSMO layers exhibit a reduced Curie temperature compared to the bulk while antiferromagnetic order in the LSFO layers persists up to the bulk Neél temperature. Moreover, we find that aligning the LSMO magnetization by a magnetic field within the (001) surface plane leads to a reorientation of the Fe moments as well maintaining a perpendicular orientation of Fe and Mn moments. This perpendicular alignment is due to the frustrated exchange coupling at the LSMO/LSFO interface.

Competing interactions in ferromagnetic/antiferromagnetic perovskite superlattices

“…For example, the spins within the surface layer of a G-type AF such as La1-xSrxFeO3 are compensated, and exchange interactions are predicted to occur via the spin-flop mechanism [6,7]. We have recently confirmed this prediction in superlattices consisting of alternating six unit cell thick La0.7Sr0.3MnO3 (LSMO) and La0.7Sr0.3FeO3 (LSFO) layers [8]. In the present study, we show that the AF and FM properties in this superlattice system exhibit dissimilar dependencies on temperature and sublayer thickness and we identify the importance of short-range electronic effects (i.e.…”

“…superconductivity or ferromagnetism) at interfaces despite the fact that it does not exist in the constituent materials. [6][7][8] Epitaxial layers interact via strain, electrostatic, and magnetic effects, all of which are highly sensitive to atomic-scale features. For example, the spins within the surface layer of a G-type AF such as La1-xSrxFeO3 are compensated, and exchange interactions are predicted to occur via the spin-flop mechanism [6,7].…”

Correlated domain structure in perovskite oxide superlattices exhibiting spin-flop coupling

“…5 For a sublayer thickness of six unit cells (~2.4 nm), we obtain a system where the LSMO sublayer remains FM, but the anisotropy of the LSFO layer has weakened sufficiently such that the direction of the AF spin axis can be reoriented by an applied magnetic field, mediated by a spin-flop coupling with the adjacent FM layers. [6][7][8][9] This behavior is in contrast to previous reports of exchange bias in the LaFeO 3 /Co (AF oxide/FM metal) system where the anisotropy of the thick LaFeO 3 layer is able to pin the adjacent Co layer, causing a horizontal shift of the magnetic hysteresis loops. [10][11] This exchange bias lies at the heart of many magnetic devices used in magnetic recording read heads and magnetic random access memory devices, while device applications for spin-flop coupling remains largely unexplored.…”

“…9 In this work, we investigated the correlation between the AF and FM domains as a function of temperature in this isostructural superlattice system using photoemission electron microscopy. These images confirm the perpendicular alignment between the AF spin axis and the Mn magnetization such that each micrometer-sized AF domain corresponds to two types of smaller (~200 nm wide) FM domains.…”

Strain-induced magnetization control in an oxide multiferroic heterostructure

“…Transition-metal oxides with perovskite structure are 38 promising in this context, as they display strong correlation 39 between spin, charge, orbital, and lattice degrees of freedom, 40 thus potentially providing multiple ways to influence mag-41 netism [13][14][15]. It has been previously shown that the total 42 magnetic moment [16,17], the coercive field [18], the magnetic 43 anisotropy [19,20], and the Curie temperature [17,21] [25].…”