Joo-Hyung Kim

Epitaxial colossal magnetoresistive La0.67(Sr,Ca)0.33MnO3 films on Si

La0.67(Sr,Ca)0.33MnO3 (LSCMO) films have been grown by a pulsed-laser deposition technique on Si(001) substrates buffered with Bi4Ti3O12/CeO2/yttrium-stabilized zirconia (YSZ) heteroepitaxial layers. X-ray diffraction has revealed cube-on-cube growth of an epitaxial Bi4Ti3O12/CeO2/YSZ/Si heterostructure whereas the LSCMO layer grows in the “diagonal-on-side” manner on top of the Bi4Ti3O12 (BTO) template. The maximum temperature coefficient of resistivity (TCR)=4.4% K−1 and colossal magnetoresistance (CMR) Δρ/ρ∼2.9% kOe−1 have been reached at 294 K. This was achieved due to the successive improvement of c-axis orientation of the layers: Full widths at half-maximum 0.65°, 0.58°, 0.65°, 1.13°, and 0.18° in LSCMO/BTO/CeO2/YSZ/Si stack, respectively. As a prototype of an uncooled bolometer, heteroepitaxial CMR structure on Si demonstrates, at 294 K, the noise equivalent temperature difference of 1.2 μK/√Hz@30 Hz.

Free-standing epitaxial La1−x(Sr,Ca)xMnO3 membrane on Si for uncooled infrared microbolometer

Ar ion beam etching and inductively coupled SF6 and C4F8 plasma-etching processes have been employed to fabricate free standing membrane from the heteroepitaxial La1−x(Sr,Ca)xMnO3(50nm)∕Bi4Ti3O12(100nm)∕CeO2(40nm)∕YSZ(30nm) film structure pulsed laser deposited on Si(001) wafer. We demonstrate feasibility to use epitaxial colossal magnetoresistive manganite film as thermally isolated self-supporting membrane for uncooled infrared microbolometer applications.

The effect of strained Si1-xGex and Si1-yCy layers for La0.75Sr0.25MnO3 films grown on oxide-buffered Si substrates.

We report the effect of strain on the structural and electrical properties of colossal magnetoresistive (CMR) La0.75Sr0.25MnO3 (LSMO) films grown on Bi4Ti3O12/CeO2/ yttrium-stabilized-zirconia-buff ...

MICROFABRICATION OF EPITAXIAL La1−x (Sr,Ca) x MnO3 IR BOLOMETER ON Si

ABSTRACT Self supported free standing heteroepitaxial La1−x (Sr,Ca) x MnO3 (LSCMO) membranes grown on Bi4Ti3O12(BTO)/CeO2/YSZ buffered Si substrates have been microfabricated by Ar ion beam etching (IBE) and SF6/C4F8 inductively coupled plasma (ICP) etching technique. The electrical property of free standing membrane was compared to as-grown sample by four point measurement. These results demonstrate feasibility to use heteroepitaxial oxide film structures with conventional photoresist patterning as thermally isolated membranes for infrared microbolometers.

Epitaxial colossal magnetoresistive/ferroelectric heterostructures on Si

We report on processing and properties of La0.67(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.