Magnetic depth profile of a modulation-dopedLa1−xCaxMnO3exchange-biased system

Abstract

Recent magnetometry measurements in modulation-doped La 1−x Ca x MnO 3 suggested that a net magnetization extends from the ferromagnetic layers into the adjacent antiferromagnet layers. Here we test this hypothesis by polarized neutron reflectometry, which allows us to determine the depth resolved magnetization profile. From fits to the reflectivity data we find that the additional magnetization does not occur at the ferromagnetic/ antiferromagnetic interfaces, but rather in a thin region of the first antiferromagnetic layer adjacent to the interface with the substrate.

Polarization screening-induced magnetic phase gradients at complex oxide interfaces

“…Intuitively, one would expect that the transition from FM metallic to paramagnetic insulating phases at the top LSMO interface would significantly reduce room temperature magnetization. To probe this, we use polarized neutron reflectometry (PNR), a scattering technique that allows us to measure the depth-resolved magnetic structure and is used to isolate individual magnetic layers in a thin-film heterostructure 16,[51][52][53][54] . Figure 6 shows the result of PNR measurements conducted at 298 K with a 1 T field applied along the substrate [100] direction.…”

Uncompensated magnetization and exchange-bias field in La0.7Sr0.3MnO3/YMnO3 bilayers: The influence of the ferromagnetic layer

“…For the FM LSMO layer, deposited immediately after the o-YMO one, the parameters were 10 Hz repetition rate and 0.35 (0.38) mbar oxygen pressure, 8 (30) nm thickness and at the same laser fluency and substrate temperature, for sample A (B). In order to corroborate the contribution of the FM layer in the M E -shift we have decreased further the oxygen concentration to deposit the LSMO film in sample C (oxygen pressure 0.10 mbar) with a larger thickness of 225 nm decreasing in this way its coercivity.…”

“…We remark that unexpected phenomena can occur at oxide interfaces. A recent study, for example, found an excess magnetization produced at the interface between STO and an AFM La 1/3 Ca 2/3 MnO 3 layer, 30 which origin remains unclear. In our case the large m shift valuesactually a giant M E effect -indicate that a large contribution should come from the FM layer.…”

Influence of the Thickness of the Ferro- and Antiferromagnetic Phases on Magnetic Properties in Epitaxial Heterostructures Based on Exchange Biased La-Ca-Mn-O System

“…The effects at the interface between the FM and AF layers were found among the main reasons for such a behavior, meaning that at the interfaces-in addition to the type of antiferromagnetic material where research has to focus-the F/AF multilayers show a collective contribution due to the high number of interfaces. Polarized neutron reflectometry measurements on F-LCMO/AF-LCMO superlattices, which permitted determining the depth-resolved magnetization profile, showed that additional magnetization does not occur at the ferromagnetic/antiferromagnetic interfaces, but rather in a region of the first antiferromagnetic layer adjacent to the interface with the substrate [5]. Therefore, the magnetization structure in these superlattices, possibly influenced by the complex electronic and magnetic interactions both at the F/AF interfaces and bulk, is more complex than that expected from nominal chemical doping profile.…”