Direct observation of temperature dependent magnetic domain structure of the multiferroic La0.66Sr0.34MnO3/BiFeO3 bilayer system by x-ray linear dichroism- and x-ray magnetic circular dichroism-photoemission electron microscopy

Abstract

Low-thickness La0.66Sr0.34MnO3 (LSMO)/BiFeO3 (BFO) thin film samples deposited on SrTiO3 were imaged by high resolution x-ray microscopy at different temperatures. The ultra-thin thickness of the top layer allows to image both the ferromagnetic domain structure of LSMO and the multiferroic domain structure of the buried BFO layer, opening a path to a direct observation of coupling at the interface on a microscopic level. By comparing the domain size and structure of the BFO and LSMO, we observed that, in contrast to LSMO single layers, LSMO/BFO multilayers show a strong temperature dependence of the ferromagnetic domain structure of the LSMO. Particularly, at 40 K, a similar domain size for BFO and LSMO is observed. This indicates a persistence of exchange coupling on the microscopic scale at a temperature, where the exchange bias as determined by magnetometer measurements is vanishing.

Anomalous Electronic Anisotropy Triggered by Ferroelastic Coupling in Multiferroic Heterostructures

“…Plenty of investigations have been devoted to combinations of strong FM CoFe/BFO [ 18,19 ] and doped manganite/BFO. [ 20,22,23 ] However, limited by polarization screening length and G-type AFM structure, most BFO-based devices are integrated with either ultra thin layers or polycrystalline iron alloys in which the underlying ferroelastic twin structures [ 24,25 ] are somewhat neglected. In this study, using the model system of multiferroic BFO, the periodic domain structures of BFO are likely to serve as domain engineering templates to control the structural inhomogeneity of similar perovskite oxides via ferroelastic strain coupling.…”

Influence of epitaxial BiFeO3 on superparamagnetic behavior of CoFeB thin film

“…BiFeO 3 (BFO), as a promising single phase multiferroic material at room temperature, is a potential candidate for realizing electric control of magnetism-the pivot for nextgeneration memories. [1][2][3][4][5][6][7][8][9] Plenty of work has been devoted to understand magnetic properties of BFO [10][11][12][13][14][15] and its coupling behaviors with adjacent magnetic materials. [16][17][18][19][20] Both exchange bias and exchange coupling have been observed in BFO-ferromagnetic (FM) bilayers, which could be modulated by both the types of ferroelectric domain walls 16 and the epitaxial strain states.…”