Ferromagnetic and charge ordering competition in strained thin films of La1−xCaxMnO3 system

Vlakhov, E.; Nenkov, K.; Donchev, T.G.; Mateev, E.; Chakalov, R. A.

doi:10.1016/j.vacuum.2004.07.023

Cited by 7 publications

(8 citation statements)

References 8 publications

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“…Therefore, making evident the very relevant role of strain on the physics of manganites. The effects of strain on the magnetic and transport properties of La 1-x Ca x MnO 3 (LCMO) films have been analyzed by several authors [8][9][10][11][12][13][14][15][16][17][18] as well as in LSMO films [19][20][21] . Nevertheless, the concurrence of masking effects, such as partial relaxation [8][9][10][11][12][13][14][15] , island growth morphology [8,9] or structural defects, etc., have hindered a clear comprehension of the real role of interfacial strain in manganite thin films.…”

Section: Introductionmentioning

confidence: 99%

Interfacial Strain: The Driving Force for Selective Orbital Occupancy in Manganite Thin Films

Abad¹,

Laukhin²,

València³

et al. 2007

Adv Funct Materials

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Complex oxides with perovskite structure are the ideal arena to study a plethora of physical properties including superconductivity, ferromagnetism, ferroelectricity, piezoelectricity and more. Among them, transition metal oxides are especially relevant since they present large electronic correlations leading to a strong competition between lattice, charge, spin, and orbital degrees of freedom. In particular, manganese perovskites oxides exhibit half‐metallic character and colossal magnetoresistive response rendering them as the ideal materials to develop novel concepts of oxide‐electronic devices and for the study of fundamental physical interactions. Due to the close similarity between kinetic energy of charge carriers and Coulomb repulsion, tiny perturbations caused by small changes in temperature, magnetic or electric fields, strain and so forth may drastically modify the magnetic and transport properties of these materials. In particular clarifying the role of interfacial strain in manganite thin films is interesting not only for device applications but also for basic understanding of physical interactions. A better comprehension of such strongly correlated systems might lead to control the different degrees of freedom in a near future contributing to the development of the so called orbitronics, i.e. controlling and modifying at will the orbital orientation of the 3d levels in transition metals. Here we reveal the importance of interfacial strain in high quality epitaxial thin films of La2/3Ca1/3MnO3 (LCMO), grown on top of SrTiO3 (STO) and NdGaO3 (NGO) (001)‐oriented substrates. We show that in such systems interfacial strain due to lattice mismatch lifts the degeneracy of the eg and t2g orbitals close to the film/substrate interface inducing Jahn‐Teller like distortions and promoting selective orbital occupancy and the appearance of an orbital glass insulating state in an otherwise ferromagnetic metallic material. These results highlight the role of strain and identify it as a key parameter in orbital control.

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Section: Introductionmentioning

confidence: 99%

Interfacial Strain: The Driving Force for Selective Orbital Occupancy in Manganite Thin Films

Abad¹,

Laukhin²,

València³

et al. 2007

Adv Funct Materials

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“…[6][7][8][9][10][11][12][13][14][15][16] In this work, we investigate the magnetotransport properties of fully commensurate epitaxial La 0.7 Sr 0.3 MnO 3 thin films grown by reactive molecular-beam epitaxy. Our films span a biaxial strain range from Ϫ2.3% to +3.2%, and we find excellent agreement between the measured Curie temperatures and the model of Millis et al 5 The films were grown on nine commercially available perovskite substrates: ͑100͒ p LaAlO 3 , ͑001͒ LaSrGaO 4 , ͑110͒ NdGaO 3 , ͑100͒ ͑LaAlO 3 ͒ 0.3 -͑SrAl 0.5 Ta 0.5 O 3 ͒ 0.7 ͑LSAT͒, ͑100͒ SrTiO 3 , ͑110͒ DyScO 3 , ͑110͒ GdScO 3 , ͑110͒ SmScO 3 , and ͑110͒ NdScO 3 , where the subscript p indicates pseudocubic indices.…”

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confidence: 99%

Effect of biaxial strain on the electrical and magnetic properties of (001) La0.7Sr0.3MnO3 thin films

Adamo¹,

Ke²,

Wang³

et al. 2009

Applied Physics Letters

192

169

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We have studied the effect of biaxial strain on thin films of (001) La0.7Sr0.3MnO3. We deposited films by reactive molecular-beam epitaxy on different single crystalline substrates, varying the substrate-induced biaxial strain from −2.3% to +3.2%. Magnetization and electrical transport measurements reveal that the dependence of the Curie temperature on biaxial strain is in very good agreement with the theoretical predictions of Millis et al

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“…In the present paper, we focus on the low-temperature regime where the presence of phase separation in the appropriate manganate systems has been directly verified, e.g., by means of scanning tunneling microscopy (STM) on thin films 11 . Transport measurements reveal metastability and history dependence near the percolation threshold (x ≈ 0.2), confirming phase separation in both film 12,13 and crystalline 14,15 samples. Using simple microscopic models 2,16 it can readily be shown 16 that the hole concentration x indeed controls the balance between the FM and AFM tendencies of the system.…”

Section: Introductionmentioning

confidence: 62%

Inhomogeneous phases in a double-exchange magnet with long range Coulomb interactions

2008

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We consider a model with competing double-exchange (ferromagnetic) and super-exchange (antiferromagnetic) interactions in the regime where phase separation takes place. The presence of a long range Coulomb interaction frustrates a macroscopic phase separation, and favors microscopically inhomogeneous configurations. We use the variational Hartree-Fock approach, in conjunction with Monte-Carlo simulations to study the geometry of such configurations in a two-dimensional system. We find that an array of diamond shaped ferromagnetic droplets is the preferred configuration at low electronic densities, while alternating ferromagnetic and anti-ferromagnetic diagonal stripes emerge at higher densities. These findings are expected to be relevant for thin films of colossal magneto-resistive manganates.

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Ferromagnetic and charge ordering competition in strained thin films of La1−xCaxMnO3 system

Cited by 7 publications

References 8 publications

Interfacial Strain: The Driving Force for Selective Orbital Occupancy in Manganite Thin Films

Interfacial Strain: The Driving Force for Selective Orbital Occupancy in Manganite Thin Films

Effect of biaxial strain on the electrical and magnetic properties of (001) La0.7Sr0.3MnO3 thin films

Inhomogeneous phases in a double-exchange magnet with long range Coulomb interactions

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