Exotic magnetic anisotropy map in epitaxial La0.7Ca0.3MnO3films

Abstract

We report the observation between 40 and 120 K of anomalous magnetic hysteresis loops in thin epitaxial films of La 0.7 Ca 0.3 MnO 3 grown on ferroelectric BaTiO 3 . These hysteresis loops display extremely unusual features: after switching at coercivity, the magnetization overshoots the eventual high-field value. We study the strains in the film and substrate with x-ray diffraction and propose a model of two magnetic moment populations with different magnetoelastic anisotropies. The relative weights of both populations can be estimated by comparison with twin samples of La 0.7 Ca 0.3 MnO 3 films on nonferroelectric SrTiO 3 . We propose that the observed magnetization overshoots the result from differences in the magnetostriction balance as the applied magnetic field increases. The picture of a nonuniform strain field in La 0.7 Ca 0.3 MnO 3 on BaTiO 3 , caused by the corrugation of the ferroelectric domains in the rhombohedric phase of BaTiO 3, is compatible with the magnetic granular behavior observed in the temperature and field dependences of the magnetization as well as in the low temperature magnetoresistance exhibited by the epitaxial film.

Ferroelectric substrate effects on the magnetism, magnetotransport, and electroresistance of La0.7Ca0.3MnOAlberca1, Munuera2, Tornos3 et al. 2012Phys. Rev. BSelf Cite283210View full textAdd to dashboardCite

“…We have previously 18 reported structural results as a function of temperature for La 0.7 Ca 0.3 MnO 3 /BaTiO 3 samples exhibiting exotic Matteucci-like behavior obtained from coplanar and grazing incidence x-ray diffraction (GIXD) synchrotron studies. We found good epitaxial adherence of La 0.7 Ca 0.3 MnO 3 to BaTiO 3 in spite of the complexity of the Although some debate still exists on the crystallographic description of the low-temperature phases of BaTiO 3 (Refs.…”

“…7 19) and enhanced tendency to microphase separation where the presence of an antiferromagnetic (AFM) insulating state is more likely. 20 Our previous study 18 focused on the appearance of anomalous magnetic hysteresis loops, so called Matteucci cycles, in a set of thin La 0.7 Ca 0.3 MnO 3 /BaTiO 3 films. We interpreted these results in terms of the existence of two populations of magnetic moments: a majority which aligns in plane with a magnetic field and a minority, whose relative abundance shows temperature dependence with a maximum near 120 K, which lies out of plane.…”

Modulation of the properties of thin ferromagnetic films with an externally applied electric field in ferromagnetic/piezoelectric/ferromagnetic hybrids

“…[10][11][12] Finally, an interesting class of hybrids that is intensively studied recently is the one composed of FM films adjacent to a piezoelectric (PE) substrate. [13][14][15][16][17][18][19] These hybrids have attracted the interest of researchers, since except for basic science they are promising for numerous devices and sensors, as for instance in magnetic recording for information storage.…”

Controllable magnetization and resistivity jumps of manganite thin films on BaTiO3 substrate

“…The magnetization jump becomes especially interesting for the La 1−x Sr x MnO 3 (LSMO) and La 1−x Ca x MnO 3 (LCMO) thin films grown on BTO substrate since it gives rise to a giant and reversible magnetocaloric effect. 34 For LSMO/BTO 29 and LCMO/BTO [30][31][32][33] thin films, resistivity jumps have also been observed during the BTO structural transition. Surprisingly, both upward and downward jumps have been observed for the LCMO/BTO system, implying that the physical origin of the jumps still remains unclear.…”

“…[5][6][7][8][9] In particular, ferroelectric substrate such as BaTiO 3 (BTO) offers additional tunability of strain since the lattice structure of BTO can be influenced by electric field. [10][11][12][13] In bulk, on cooling the structure of BTO changes from cubic to tetragonal at ferroelectric Tc of ∼ 400 K, and from tetragonal to monoclinic at 268 K, and from monoclinic (M) to rhombohedral (R) at 183 K. 14,15 Even without applying electric field, it has been shown that the structural transitions of the BTO induces distinct jumps of magnetization of 3d metals, [16][17][18][19][20][21] [29][30][31][32][33] films grown epitaxially on BTO substrates. The magnetization jump becomes especially interesting for the La 1−x Sr x MnO 3 (LSMO) and La 1−x Ca x MnO 3 (LCMO) thin films grown on BTO substrate since it gives rise to a giant and reversible magnetocaloric effect.…”