Colossal magnetoresistance in ultrathin epitaxial La0.75Sr0.25MnO3 films

Khartsev, Sergiy; Johnsson, P.; Grishin, Alexander M.

doi:10.1063/1.372191

Cited by 74 publications

(34 citation statements)

References 7 publications

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“…Compressive strain usually reduces the resistivity and shifts T C towards higher temperature. These effects have been confirmed in La 0.7 Ca 0.3 MnO 3 films 6,7 and La 0.7 Sr 0.3 MnO 3 films [8][9][10][11][12] grown on various substrates.…”

Section: Introductionmentioning

confidence: 68%

“…In epitaxial films, biaxial strain has been reported to have very strong effect on the changes in T C and insulator-metal transition temperature (T IM ) [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . Several publications have reported that both T C and T IM can vary with film thickness [14][15][16][17][18][19][20][21][22][23] .…”

Section: Introductionmentioning

confidence: 99%

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Influence of strain relaxation on magnetotransport properties of epitaxial La_0.7Ca_0.3MnO₃films

Siwach

Singh

Srivastava

2006

J. Phys.: Condens. Matter

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In this paper, we have studied the effect of strain relaxation on magneto-transport properties of La 0.7 Ca 0.3 MnO 3 epitaxial films (200 nm thick), which were deposited by pulsed laser deposition technique under identical conditions. All the films are epitaxial and have cubic unit cell. The amount of strain relaxation has been varied by taking three different single crystal substrates of SrTiO 3 , LaAlO 3 and MgO. It has been found that for thicker films the strain gets relaxed and produces variable amount of disorder depending on the strength of strain relaxation. The magnitude of lattice relaxation has been found to be 0.384, 3.057 and 6.411 percent for film deposited on

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Section: Introductionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Influence of strain relaxation on magnetotransport properties of epitaxial La_0.7Ca_0.3MnO₃films

Siwach

Singh

Srivastava

2006

J. Phys.: Condens. Matter

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“…In epitaxial thin films grown on perovskite substrates, the biaxial strain that can be induced by lattice mismatch with the underlying substrate, film thickness, oxygen content, etc., provides an additional degree of freedom and, hence, influences the magnetic and transport properties. [11][12][13][14][15][16][17] In the case of a film grown on a given substrate, the strain mainly depends on the thickness. Beyond a critical film thickness, the strain is gradually relaxed and this aspect also has decisive influence on magnetic and transport properties, such as magnetization, T C , and T IM .…”

Section: Introductionmentioning

confidence: 99%

Thickness dependent transport properties of compressively strained La0.88Sr0.12MnO3 ultrathin films

Prasad

Singh

et al. 2008

Journal of Applied Physics

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Thickness dependent magnetic and transport properties of compressively strained La 0.88 Sr 0.12 MnO 3 thin films grown on single crystalline SrTiO 3 ͑100͒ substrates have been studied. All films exhibit a large enhancement of ϳ130 K in T C / T IM as compared to that of the bulk target ͑T C ϳ 175 K͒. This has been explained in terms of suppression of the cooperative Jahn-Teller distortion due to in-plane compressive strain. The T C / T IM of the 5 nm film is 315 K/318 K and slightly increases for film thicknesses Յ25 nm. At higher film thicknesses, ϳ60 nm, the T C / T IM starts decreasing. At T Ͼ T IM , the electrical transport is due to thermally activated hopping of small polarons. The activation energy is found to be sensitive to film thickness and shows a minimum at around L ϳ 15-25 nm, which corresponds to the maximum of T C / T IM . All films possess large magnetoresistances ͑MRs͒ in the vicinity of room temperature. Low as well as high field MRs are observed to nearly double as the film thickness increases from 5 nm ͑MRϳ 28% / 3 T͒ to 60 nm ͑MR% ϳ 50% / 3 T͒. Thicker films ͑L Ն 25 nm͒ are found to exhibit sufficiently large temperature coefficients of resistivities, ϳ4% -5% / K, which could be suitable for bolometric applications.

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“…Conversely, studies concerned with the effect of strain have neglected finite size scaling. [13] Clearly it is necessary to consider both possible effects on an equal footing and it would be desirable to assign a particular amount of change in transition temperature to a particular cause. In this paper, we report a systematic study of the Curie temperature of a series of ferromagnetic LSCO films with different thickness on a variety of substrates.…”

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confidence: 99%

Separation of the strain and finite size effect on the ferromagnetic properties of La0.5Sr0.5CoO3 thin films

Xie

Budnick

Wells

et al. 2007

Applied Physics Letters

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The ferromagnetic properties of epitaxial La0.5Sr0.5CoO3 thin films have been studied. The magnetic transition is affected by both strain and finite thickness. We have used a series of films of different thickness and on different substrates in order to quantitatively determine the change in Curie temperature contributed by each effect. The phase diagram of TC versus in-plane strain suggests that the ferromagnetic transition temperature is suppressed by tensile strain and enhanced by compressive strain. The general method of separating strain and finite thickness effects should be applicable to any ordering phase transition in thin films.Thin films of perovskite oxide materials have attracted great attention lately due to their potential technological applications based on a variety of appealing physical properties, such as colossal magnetoresistivity, ferroelectricity, and high-Tc superconductivity. The properties of films differ from the corresponding bulk typically due to a combination of three factors. Firstly, defect levels are often higher in films. Oxygen deficiency is the most common defect and will typically suppress the transition temperature due to the decrease of doped hole density or the destruction of metal-oxygen hopping pathways.[1] Secondly, finite size effects may be important. For example, the Curie temperature (T C ) for a ferromagnetic thin film will be reduced when the spin-spin correlation length exceeds the film thickness. The thickness-dependent Curie temperature has been most carefully studied in simple metallic films of Fe, Co, Ni and Gd. [2, 3] A similar scaling effect has also been found in ferroelectric materials. [4] Thirdly, strain incorporated into films due to effects such as a lattice mismatch with the substrate may also alter the phase transition through changes in fundamental interactions that depend upon atomic spacing. Strain in thin films is often thought of as analogous to that induced in high-pressure experiments on bulk materials. However, a much larger strain can be achieved in films than that in bulk and the strain in films is usually biaxial rather than hydrostatic or uniaxial as in most bulk pressure experiments. The induced strain can modify the lattice structure, the critical temperature for phase transition, and sometimes the nature of the phases present themselves. [5,6,7] La 0.5 Sr 0.5 CoO 3 (LSCO) is a highly doped ferromagnetic oxide material with perovskite structure and has desirable properties of high electrical conductivity and large magnetoresistance. [8,9] Thin film LSCO is a candidate for applications such as electrodes for fuel cells, ferroelectric memory and spin valve devices. The first concern noted above, the oxygen content in LSCO films, can be controlled by carefully optimizing growth conditions so that stoichiometry of oxygen can be maintained. [10] However, the finite size and strain effects are intrinsic to the film, and it is not trivial to separate the influence of these two effects on a particular film. Recently, Fuchs et al [11] and Andre...

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Colossal magnetoresistance in ultrathin epitaxial La0.75Sr0.25MnO3 films

Cited by 74 publications

References 7 publications

Influence of strain relaxation on magnetotransport properties of epitaxial La_0.7Ca_0.3MnO₃films

Influence of strain relaxation on magnetotransport properties of epitaxial La_0.7Ca_0.3MnO₃films

Thickness dependent transport properties of compressively strained La0.88Sr0.12MnO3 ultrathin films

Separation of the strain and finite size effect on the ferromagnetic properties of La0.5Sr0.5CoO3 thin films

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Colossal magnetoresistance in ultrathin epitaxial La0.75Sr0.25MnO3 films

Cited by 74 publications

References 7 publications

Influence of strain relaxation on magnetotransport properties of epitaxial La0.7Ca0.3MnO3films

Influence of strain relaxation on magnetotransport properties of epitaxial La0.7Ca0.3MnO3films

Thickness dependent transport properties of compressively strained La0.88Sr0.12MnO3 ultrathin films

Separation of the strain and finite size effect on the ferromagnetic properties of La0.5Sr0.5CoO3 thin films

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Influence of strain relaxation on magnetotransport properties of epitaxial La_0.7Ca_0.3MnO₃films

Influence of strain relaxation on magnetotransport properties of epitaxial La_0.7Ca_0.3MnO₃films