Epitaxial Colossal Magnetoresistive/Ferroelectric Heterostructures on Si

Abstract

We report on processing and properties of La_0.67(Sr, Ca)_0.33MnO₃ (LSCMO) films grown by pulsed laser deposition technique on Si(001) substrates buffered with Bi₄Ti₃O₁₂/CeO₂/YSZ heteroepitaxial layers. X-ray diffraction shows cube-on-cube growth of epitaxial Bi₄Ti₃O₁₂/CeO₂/YSZ/Si heterostructure whereas the LSCMO layer grows in the “diagonal-on-side” manner onto the Bi₄Ti₃O₁₂ (BTO) template. High resolution TEM images demonstrate sharp interfaces between the buffer layers and LSCMO film as well as rare misfit dislocations on the CeO₂/YSZ interface. LSCMO film processing conditions have been optimized to get maximum temperature coefficient of resistivity TCR = 4.4% K^{− 1} and colossal magnetoresistance (CMR) Δ ρ/ρ ∼ 2.9% kOe⁻¹ @ 294 K. Almost ultimate CMR performance at room temperature has been achieved due to successive improvement of c-axis orientation of layers: full widths at half-maximum (FWHM) = 0.65, 0.58, 0.65, 1.13 and 0.18 degrees in LSCMO/BTO/CeO₂/YSZ/Si stack, respectively. Characterization of electrical noise in CMR film yields Noise Equivalent Temperature Difference (NETD) as low as 1.2 μ K/√surd Hz @ 30 Hz and 294 K.

ACKNOWLEDGMENTS

This research was supported by the Swedish Foundation for Strategic Research (SSF) through the consortium “Functional Ceramics”.