Interface magnetization transition via minority spin injection

Fang, F.; Zhai, Haowei; Ma, Xiaoxuan; Yin, Yuewei; Li, Qi; Lüpke, G.

doi:10.1063/1.4972035

Cited by 4 publications

(1 citation statement)

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“…Due to the increased distance between the first two interfacial Mn atoms arising from the displacement of first Mn atom towards the interface, the spin hopping of electrons is reduced leading to localization of spins within the orbitals of individual Mn atoms. Eventually, the double exchange mechanism gets suppressed and AFM superexchange interaction can then dominate to create an AFM bond between the first two Mn atoms near the interface [46,47]. Indeed, our DFT calculations find that the ground state spin configuration of the interfacial Mn atoms transforms from FM state to AFM state due to the ferroelectricity in BTO within the BTO-LSMO heterostructure.…”

Section: Resultsmentioning

confidence: 91%

Engineering exchange bias at the interface of self-polarized ultrathin ferroelectric BaTiO3 and ferromagnetic La0.67Sr0.33MnO3

Maity

Bansal

Dolui

et al. 2022

Preprint

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Atomic-scale interfaces of 3d transition-metal oxides are a fascinating landscape of atomic-scale interaction of spins, charge transfers, lattice distortions, and orbital reconstructions. Emergent physical phenomena originating at such interfaces have huge potential for next-generation nanoscale spintronic devices. Among them, exchange bias (EB) has been extensively studied owing to its importance for device applications such as high-density memory and magnetic sensor. Here, at the interface of epitaxially grown ferromagnetic La0.67Sr0.33MnO3 (LSMO) – ferroelectric BaTiO3 (BTO) bilayer thin films on SrTiO3 (STO) substrates, we demonstrate EB coupling (exchange bias shift, HE ~50 Oe at 2 K) without any conventional antiferromagnet. Such EB coupling is observed only for LSMO and BTO layers of <10 nm thickness. Importantly, we find that the EB coupling follows a conventional training effect, bias field dependency, and temperature dependency. By undertaking X-ray magnetic circular dichroism measurements of the epitaxial heterostructures, it is observed that Ti in the BTO exhibits magnetization at 2 K which can be reversibly switched between two distinct magnetization states on switching the magnetic field direction. High resolution electron microscopy and ab initio calculations show that the displacement of Ti4+ in the highly strained ultrathin BTO displaces the interfacial Mn4+ from its centrosymmetric position in LSMO, changing its d-orbital occupancy to favour an antiferromagnetic spin configuration. This in turn leads to an interfacial EB effect from ferroelectric polarization. This work represents an important step towards a new class of memory devices by controlled ferroic polarization and EB coupling in the same device.

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Section: Resultsmentioning

confidence: 91%