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

Abstract

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

Impact of strain on metamagnetic transitions in Sm0.5Sr0.5MnO3 thin films

“…We would like to mention here that at thickness ~200 nm, the strain is generally expected to be completely relaxed. 11,12 However, in the present case presence of strain could be attributed to the larger difference between the substrate and materials lattice parameters.…”

“…The strain caused by the difference in the lattice parameters of the substrate and the material is one of the external stimulus that is believed to play a key role in controlling the fraction and size of the ferroic phases such as the FMM and AFM/COI, which coexist due to the strong coupling between the spin, lattice and orbital degrees of freedom. [11][12][13][14][15] The tensile strain stretches the MnO 6 octahedra along the film plane (compression in the out-of-plane direction) and hence enhances the Jahn-Teller (JT) distortion that favors the AFM/COI. In contrast, the elongation of the MnO 6 in the out-of-plane direction by the compressive strain weakens the JT distortion and favours the FM-double exchange (DE), which enhances the FMM phase.…”

“…In contrast, the elongation of the MnO 6 in the out-of-plane direction by the compressive strain weakens the JT distortion and favours the FM-double exchange (DE), which enhances the FMM phase. 11,12 The strain is generally relieved by formation of defects and it has been shown that the creation of defects also favors the FMM at the cost of COI. 11,12 The magnitude of PS, i.e., fraction and dimensionality of the coexisting electronic phases is strongly dependent on band width (W), which is controlled by the average size of the A-site cations of the ABO 3 lattice.…”

“…11,12 The strain is generally relieved by formation of defects and it has been shown that the creation of defects also favors the FMM at the cost of COI. 11,12 The magnitude of PS, i.e., fraction and dimensionality of the coexisting electronic phases is strongly dependent on band width (W), which is controlled by the average size of the A-site cations of the ABO 3 lattice. The degree of phase separation increases with decreasing W. Consequently, at small W even a relatively smaller strain is expected to have more pronounced effect on magnetotransport properties.…”

Ferromagnetism, insulator-metal transition and magnetotransport in Pr0.58Ca0.42MnO3films: role of microstructural perturbations

“…Here we would like to mention that the strain arising owing to the distinct lattice constants of the film material and the substrate is one of the key external stimuli and has profound impact on the size and fraction of the FMM and AFM/COI phases [23][24][25][26][27][28]. The tensile strain enhances the Jahn-Teller (JT) distortion by stretching the MnO 6 octahedra along the film plane and hence favors the AFM/COI phase.…”