Electronic and magnetic structure of the(LaMnO3)2n/(SrMnO

Abstract

We study the magnetic structure of the ͑LaMnO 3 ͒ 2n / ͑SrMnO 3 ͒ n superlattices from density-functional calculations. In agreement with the experiments, we find that the magnetism changes with the layer thickness n. The reason for the different magnetic structures is shown to be the varying potential barrier across the interface, which controls the leakage of the Mn-e g electrons from the LaMnO 3 side to the SrMnO 3 side. This in turn affects the interfacial magnetism via the carrier-mediated Zener double exchange. For the n = 1 superlattice, the Mn-e g electrons are more or less spread over the entire lattice so that the magnetic behavior is similar to the equivalent alloy compound La 2/3 Sr 1/3 MnO 3 . For larger n, the e g electron transfer occurs mostly between the two layers adjacent to the interface, thus leaving the magnetism unchanged and bulklike away from the interface region.

Evolution of magnetic phases and orbital occupation in(SrMnO3)n/(LaMnO3Aruta1, Adamo2, Galdi3 et al. 2009Phys. Rev. B682500View full textAdd to dashboardCite

“…2b we summarize these information by plotting the integral of the XMLD spectra at B = 1 T. Observing that for n = 1 the single SrO layers are sandwiched between two interfaces, namely the interfacial MnO 2 planes, the intrinsic properties of SMO block are not recovered. On the contrary, for bigger values of n an AFM contribution from the SMO layer could survive, as it has been theoretically predicted by Nanda and Satpathy [7] together with a contribution from the LMO block. Also in several experimental works [5,24,25] the AFM region has been located in the SMO blocks too.…”

“…In the particular case of (SMO) n /(LMO) 2n the La:Sr ratio is 2:1, in analogy with the optimal composition of La 2/3 Sr 1/3 MnO 3 (LSMO). In such a case, the metal-insulator transition (MIT) and the magnetic properties depend on the thickness of the constituent blocks [4,5,6,7], although in a non trivial way. Indeed, saturation magnetization does not linearly decrease with n [4] and both fast and viscous spin populations are present, the latter associated to FM/AFM pinning [8].…”

“…However, the knowledge of the mutual dependence of the AFM and FM phases with n is still uncertain, but it could open further perspectives in the control of the low dimensional magnetic properties, thus in the engineering of the TMO magnetic heterostructures. In addition, as the role of interfacial Mn e g electrons is known to be important, the influence of strain and reduced dimensionality on the transport properties requires some attention [6,7,9,10]. In the case of LMO/SMO SLs the two materials widely change their behavior with respect to bulk.…”

“…In this context, strain driven spin-orbital coupled states arising in manganites make the interfaces between these compounds very interesting for engineering unique collective states. As a matter of fact, a certain amount of theoretical and experimental studies on superlattices (SLs) composed by the two AFM insulators, SrMnO 3 (SMO) and LaMnO 3 (LMO), appeared in literature during the last years [4,5,6,7,8,9,10,11,12]. The ordered sequence of the atomic layers in the digital SMO/LMO SLs [4,5], together with the electronic reconstruction arising from the interfacial Mn 3+ /Mn 4+ mixed valence, give rise to peculiar transport, magnetic and orbital properties, when different layering and strain conditions occur.…”

Effect of strain on the orbital and magnetic ordering of manganite thin films and their interface with an insulator

“…The lattice mismatch between the different layers gives rise to a uniaxial strain which may affect the bulk properties of a thin manganite [27][28][29][30][31][32] and/or the electronic reconstruction at its interface.…”