Orbital-State-Mediated Phase-Control of Manganites

Konishi, Yukiko; Fang, Zhong; Izumi, Makoto; Manako, T.; Kasai, Masahiro; Kuwahara, H.; Kawasaki, Masashi; Terakura, Kiyoyuki; Tokura, Y.

doi:10.1143/jpsj.68.3790

Cited by 320 publications

(248 citation statements)

References 13 publications

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“…Recent theoretical work of Fang et al [56] has discussed the effect of a tetragonal distortion of cubic manganites on the magnetic ordering in terms of orbital ordering and anisotropy in the hopping integrals. Their results are in accordance to measurements on manganite films [57].…”

Section: Transport Propertiessupporting

confidence: 91%

Structure and transport properties of coherently strained La_2/3Ca_1/3MnO₃/SrTiO₃ superlattices

Klein

Herbstritt

et al. 2005

Physica Status Solidi (b)

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We have prepared high quality, coherently strained La 2/3 Ca 1/3 MnO 3 /SrTiO 3 superlattices with different modulation periods by laser molecular beam epitaxy on (001) SrTiO 3 and NdGaO 3 substrates. A detailed structural characterization was performed by high-angle X-ray diffraction (HAXRD) and low-angle X-ray reflectivity (LAXRR). All superlattices are very flat, show excellent structural coherence and very small mosaic spread (0.02°). The in-plane coherency strain was varied by changing the thickness ratio of the constituent layers allowing for a systematic variation of the resulting tetragonal distortion of LCMO. The c-axis lattice parameter of LCMO could be continuously changed from 3.87 Å to 3.79 Å. The interface roughness was analyzed by offset low-angle X-ray reflectivity and low-angle rocking curve measurements. It was found to be of the order of one unit cell with a significant part of the roughness being vertically correlated. The strain induced tetragonal distortion of LCMO was found to cause strong reduction of the paramagnetic to ferromagnetic transition temperature from about 260 to 120 K and an increase of resistivity. The transport properties in the paramagnetic regime could be well described by a small polaron hopping model. The lattice distortions were found to result in a significant increase of the polaron trapping energy. Our results show that coherently strain superlattices are an interesting model system for the systematic study of the effect of lattice distortions on the magnetic and electronic properties of the doped manganites.

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Section: Transport Propertiessupporting

confidence: 91%

Structure and transport properties of coherently strained La_2/3Ca_1/3MnO₃/SrTiO₃ superlattices

Klein

Herbstritt

et al. 2005

Physica Status Solidi (b)

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“…In general, this c-a plot obeys a simple linear relationship expressed as c-a 0 =−4 ͑a − a 0 ͒, where the coefficient represents a Poisson ratio, typically ϳ 0.3 for perovskite manganites. 10 The parameter a 0 , deduced from the intersec- tion with c = a, indicates the hypothetical lattice constant of the film under a strain-free condition, which is indeed coincident with the averaged lattice constant of bulk solidsolution crystals ͑0.3936, 0.387, and 0.3806 nm for x = 0, 0.4, and 1, respectively͒. Both ͓La3, Sr2͔ and ͓La6, Sr4͔ superlattices also satisfy the above relationship.…”

mentioning

confidence: 71%

“…The chemical potential difference at the interface would promote charge transfer between adjacent layers, but the magnitude and resultant electronic states might be altered by controlling orbital degree of freedom as demonstrated in epitaxially strained thin films. 10,11 The strain effects of interfacial manganites can be tuned by the choice of the substrate for coherent epitaxy. We have systematically synthesized the superlattices composed of LMO and SMO on single-crystalline ͑001͒ substrates of SrTiO 3 ͑STO͒ with a lattice constant ͑a sub ͒ of 0.3905 nm, La 0.3 Sr 0.7 Al 0.65 Ta 0.35 O 3 ͑LSAT͒ ͑a sub = 0.3870 nm͒, and LaAlO 3 ͑LAO͒ ͑a sub = 0.3792 nm͒ by pulsed laser deposition.…”

mentioning

confidence: 99%

La Mn O 3 ∕ Sr Mn O 3 interfaces with coupled charge-spin-orbital modulation

Yamada

Kawasaki

Lottermoser

et al. 2006

Applied Physics Letters

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The artificial perovskite superlattices composed of LaMnO3 and SrMnO3 have been investigated to elucidate the interface electronic phases created by adjoining the two Mott insulators. Charge transfer at the interface due to chemical potential difference, as observed in p-n junctions of semiconductors, can realize metallic ferromagnet instead of resulting in insulating depletion layer. The interface electronic phases strongly depend on the orbital states at the interface which can be tuned by epitaxial strain.

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“…This behavior may be indicative of the formation of a spin-glass phase or phase separation due to the large tensile strain. 17,21 In fact, using first-principles band structure calculations, Fang et al 22 and Konishi et al 23 predicted that under large tensile strain, LSMO would transition from the FM/metal to the A-type antiferromagnetic (AFM)/insulator state. Close to this boundary one might expect the LSMO layer to phase separate into FM/metal and AFM/insulator regions depending on the local variations in strain state and/or chemical composition.…”

mentioning

confidence: 99%

Strain engineering to control the magnetic and magnetotransport properties of La0.67Sr0.33MnO3 thin films

Yang

Kemik

Biegalski

et al. 2010

Applied Physics Letters

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This work studies the control of the magnetic and magnetotransport properties of La 0.67 Sr 0.33 MnO 3 thin films through strain engineering. The strain state is characterized by the tetragonal distortion (c/a ratio), which can be varied continuously between a compressive strain of 1.005 to a tensile strain of 0.952 by changing the type of substrate, the growth rate, and the presence of an underlying La 0.67 Sr 0.33 FeO 3 buffer layer. Increasing tensile tetragonal distortion of the La 0.67 Sr 0.33 MnO 3 thin film decreases the saturation magnetization, changes the temperature dependence of the resistivity and magnetoresistance, and increases the resistivity by several orders of magnitude.The perovskite oxides have been widely investigated in recent years since they possess various important physical properties such as ferromagnetism, superconductivity, and ferroelectricity. 1 In particular, La 0.67 Sr 0.33 MnO 3 (LSMO) is an attractive candidate for spintronic devices 2,3 because it displays colossal magnetoresistance (CMR) and half-metallicity, and possesses a Curie temperature, T C, above room temperature (~ 360 K). 4,5 In this material, the T C marks the transition between the ferromagnetic (FM)/ metallic and the paramagnetic (PM)/ insulating states, as well as the peak in the CMR. This correlation between the electrical and magnetic properties is explained by the double-exchange mechanism 6,7 which involves the hopping of electrons between Mn 3+ and Mn 4+ ions with parallel spin through a bridging O 2-ion. Due to the strong interactions between the charge and orbital degrees of freedom, these properties can be manipulated by a number of different parameters, including external pressure 8 , oxygen stoichiometry 9 , and the doping level. 10,11 With thin films, the epitaxial strain imposed from the underlying substrate provides an additional tuning parameter for the functional properties. It has been shown that coherently strained LSMO thin films can be grown on a wide range of different single crystal oxide substrates and that the resulting strain dramatically impacts the magnetic and magnetotransport properties of the thin films. [12][13][14][15][16] The strain state can be characterized by the tetragonal distortion, defined as the c/a ratio, where the in-plane lattice parameter of the film, a, is dictated by the lattice parameter of the substrate, and the out-of-plane lattice parameter, c, is allowed to respond accordingly. For example, Kwon et al. reported that an in-plane easy magnetization direction is observed in tensile-strained films (c/a ratio < 1) grown on (001)-oriented SrTiO 3 (STO) substrates, while compressively strained films (c/a ratio > 1) grown on (001)-oriented LaAlO 3 (LAO) substrates exhibit an out-of-plane easy axis. 12 Furthermore, it has been shown that the magnitude of this tetragonal distortion depends on the crystallographic orientation of the film and the substrate. 13,14,17 Fully strained LSMO films grown on (110)-oriented substrates show enhanced electrical and magnetic propertie...

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Orbital-State-Mediated Phase-Control of Manganites

Cited by 320 publications

References 13 publications

Structure and transport properties of coherently strained La_2/3Ca_1/3MnO₃/SrTiO₃ superlattices

Structure and transport properties of coherently strained La_2/3Ca_1/3MnO₃/SrTiO₃ superlattices

La Mn O 3 ∕ Sr Mn O 3 interfaces with coupled charge-spin-orbital modulation

Strain engineering to control the magnetic and magnetotransport properties of La0.67Sr0.33MnO3 thin films

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Orbital-State-Mediated Phase-Control of Manganites

Cited by 320 publications

References 13 publications

Structure and transport properties of coherently strained La2/3Ca1/3MnO3/SrTiO3 superlattices

Structure and transport properties of coherently strained La2/3Ca1/3MnO3/SrTiO3 superlattices

La Mn O 3 ∕ Sr Mn O 3 interfaces with coupled charge-spin-orbital modulation

Strain engineering to control the magnetic and magnetotransport properties of La0.67Sr0.33MnO3 thin films

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Structure and transport properties of coherently strained La_2/3Ca_1/3MnO₃/SrTiO₃ superlattices

Structure and transport properties of coherently strained La_2/3Ca_1/3MnO₃/SrTiO₃ superlattices