Mechanisms of anisotropy control by strain in FePt/BaTiO

A. ROMÁN; A. LÓPEZ PEDROSO; A. LO GIUDICE; L. NEÑER; D. PÉREZ; M. AGUIRRE; A. BUTERA; MARTÍN SIRENA; JAVIER GÓMEZ; L. B. STEREN

Barilcohe

Simposio; XXIII Latin American Symposium on Solid State Physics,; 2018

The design and fabrication of multiferroics (MF)is one of the main challenges for the development ofoxide spintronics. Tuning the magnetic state of nanostructuresby electric eld or strains appears to bethe key for low-energy devices. Magneto-electric andmagneto-elastic coupling at interfaces between ferromagnetic(FM) and ferroelectric (FE) layers are at theorigin of these phenomena [1]. The magnetic order andanisotropy of the FM component can be aected bythe strains induced by the FM/FE lattice mismatchwhile charge transfer between both compounds candepend on the ferroelectric polarization of the structure.A variety of FM and FE have been combinedinto articial MF, being the magnetic compounds generallyoxides or transition metal alloys. In particular,FePt/BaTiO3 seems to be a very promising system.First-principle calculations revealed recently that importantchanges of magnetic anisotropy should be observedon the FePt overlayer when BaTiO3(BTO) ispoled[2]. Moreover, BTO piezoelectric and FePt magnetostrictiveproperties make FePt/BTO heterostructurea highly tunable multiferoic by magnetic and electricelds.The measurements of the lattice symmetryand size of both, the FE and FM components of theFePt/BTO multilayer, in correlation to magnetic propertiesstudies served us to get a deep insight into themagneto-elastic coupling mechanisms in this system.To achieve our goal, we grew a series of FePt/BTOlms, with tFePt varying from 10nm to 60nm, by sputteringon SrTiO3 substrates. The quality of the lmswas probed by TEM and AFM measurements. Themagnetic characterization of the samples was doneby magnetization vs. eld and temperature measurementstogether with magnetic force microscopy.Thecrystalline structure of the constituents was investiga-ted by XRD patterns measured in dierent geometriesand temperatures. These experiments were performedat the LNLS, Campinas Brazil. The analysis of bothaspects of the system allow us to better understandthe properties of this articial structure.[1] C. A. Vaz, J. Phys: Condens. Matter, 24, 333201(2012)[2] M. Lee et al, J. Appl. Phys., 113, 17C729 (2013)