Quantifying strain dependence in “colossal” magnetoresistance manganites

Abstract

Experimental, phenomenological, and theoretical analyses are given of the dependence on strain of the ferromagnetic Tc of the colossal magnetoresistance (CMR) rare earth manganese perovskites. It is found that Tc is extremely sensitive to biaxial strain; by implication other physical properties are also. The results indicate that biaxial strain is an important variable which must be considered in the design of devices based on thin films and provide evidence in favor of the relevance of the Jahn–Teller electron-phonon coupling to the CMR phenomenon.

Disorder effects in epitaxial thin films of (La,Ca)MnO3

“…The ͑negative͒ equivalent hydrostatic pressure for this volume change can be estimated at 5 GPa, 8 which could lead to ⌬T c ӍϪ20 K, 9 too small to explain the experimental value. However, biaxial strain can have an equal or even larger effect on T c , as was recently argued by Millis et al 10 We believe, therefore, that our measured values are intrinsic for epitaxial, strained LCMO on STO, which is corroborated by similar values reported previously. 4,5,11 Note that growth on LAO indicates different behavior, with strained, epitaxial films yielding T c values around 240 K. 11 Next, we turn to the behavior of the films with small d s .…”

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

“…This results in a strain induced Jahn -Teller splitting and, in turn, in an increased tendency of the electrons to become localized by polaronic effects [15]. For bulk materials, local-structure measurements of the Mn -O bond length distribution using XAFS have provided direct evidence for a dynamic Jahn -Teller distortion of the MnO 6 octahedra [50 -52], which localizes the charge carriers and causes a high-resistance state with small polaron hopping conductivity at high temperatures.…”

Enhanced electrical and magnetic properties in La0.7Sr0.3MnO3thin films deposited on CaTiO3-buffered silicon substrates

“…This leads us to conclude that both the electrical and magnetic properties are enhanced compared to those reported in high epitaxial quality La 0.7 Sr 0.3 MnO 3 films deposited on SrTiO 3 buffered Si substrates, 39 where T MI and T C values were 350 K and 330 K, respectively. We ascribe the enhancement of these properties to the fact that the La 0.7 Sr 0.3 MnO 3 cell is under compressive in-plane strain on CaTiO 3 /Si as predicted by Millis et al 57 and also experimentally observed in Ref. 43.…”